text: /* eslint-disable */
  
  /*******************************************************************************
   * Copyright (c) 2013 IBM Corp.
   *
   * All rights reserved. This program and the accompanying materials
   * are made available under the terms of the Eclipse Public License v1.0
   * and Eclipse Distribution License v1.0 which accompany this distribution. 
   *
   * The Eclipse Public License is available at 
   *    http://www.eclipse.org/legal/epl-v10.html
   * and the Eclipse Distribution License is available at 
   *   http://www.eclipse.org/org/documents/edl-v10.php.
   *
   * Contributors:
   *    Andrew Banks - initial API and implementation and initial documentation
   *******************************************************************************/
  
  
  // Only expose a single object name in the global namespace.
  // Everything must go through this module. Global Paho.MQTT module
  // only has a single public function, client, which returns
  // a Paho.MQTT client object given connection details.
   
  /**
   * Send and receive messages using web browsers.
   * <p> 
   * This programming interface lets a JavaScript client application use the MQTT V3.1 or
   * V3.1.1 protocol to connect to an MQTT-supporting messaging server.
   *  
   * The function supported includes:
   * <ol>
   * <li>Connecting to and disconnecting from a server. The server is identified by its host name and port number. 
   * <li>Specifying options that relate to the communications link with the server, 
   * for example the frequency of keep-alive heartbeats, and whether SSL/TLS is required.
   * <li>Subscribing to and receiving messages from MQTT Topics.
   * <li>Publishing messages to MQTT Topics.
   * </ol>
   * <p>
   * The API consists of two main objects:
   * <dl>
   * <dt><b>{@link Paho.MQTT.Client}</b></dt>
   * <dd>This contains methods that provide the functionality of the API,
   * including provision of callbacks that notify the application when a message
   * arrives from or is delivered to the messaging server,
   * or when the status of its connection to the messaging server changes.</dd>
   * <dt><b>{@link Paho.MQTT.Message}</b></dt>
   * <dd>This encapsulates the payload of the message along with various attributes
   * associated with its delivery, in particular the destination to which it has
   * been (or is about to be) sent.</dd>
   * </dl> 
   * <p>
   * The programming interface validates parameters passed to it, and will throw
   * an Error containing an error message intended for developer use, if it detects
   * an error with any parameter.
   * <p>
   * Example:
   * 
   * <code><pre>
  client = new Paho.MQTT.Client(location.hostname, Number(location.port), "clientId");
  client.onConnectionLost = onConnectionLost;
  client.onMessageArrived = onMessageArrived;
  client.connect({onSuccess:onConnect});
  
  function onConnect() {
    // Once a connection has been made, make a subscription and send a message.
    console.log("onConnect");
    client.subscribe("/World");
    message = new Paho.MQTT.Message("Hello");
    message.destinationName = "/World";
    client.send(message); 
  };
  function onConnectionLost(responseObject) {
    if (responseObject.errorCode !== 0)
  	console.log("onConnectionLost:"+responseObject.errorMessage);
  };
  function onMessageArrived(message) {
    console.log("onMessageArrived:"+message.payloadString);
    client.disconnect(); 
  };	
   * </pre></code>
   * @namespace Paho.MQTT 
   */
  
  
  const Paho = {};
  
  
  Paho.MQTT = (function (global) {
  
  	// Private variables below, these are only visible inside the function closure
  	// which is used to define the module. 
  
  	var version = "@VERSION@";
  	var buildLevel = "@BUILDLEVEL@";
  	
  	/** 
  	 * Unique message type identifiers, with associated
  	 * associated integer values.
  	 * @private 
  	 */
  	var MESSAGE_TYPE = {
  		CONNECT: 1, 
  		CONNACK: 2, 
  		PUBLISH: 3,
  		PUBACK: 4,
  		PUBREC: 5, 
  		PUBREL: 6,
  		PUBCOMP: 7,
  		SUBSCRIBE: 8,
  		SUBACK: 9,
  		UNSUBSCRIBE: 10,
  		UNSUBACK: 11,
  		PINGREQ: 12,
  		PINGRESP: 13,
  		DISCONNECT: 14
  	};
  	
  	// Collection of utility methods used to simplify module code 
  	// and promote the DRY pattern.  
  
  	/**
  	 * Validate an object's parameter names to ensure they 
  	 * match a list of expected variables name for this option
  	 * type. Used to ensure option object passed into the API don't
  	 * contain erroneous parameters.
  	 * @param {Object} obj - User options object
  	 * @param {Object} keys - valid keys and types that may exist in obj. 
  	 * @throws {Error} Invalid option parameter found. 
  	 * @private 
  	 */
  	var validate = function(obj, keys) {
  		for (var key in obj) {
  			if (obj.hasOwnProperty(key)) {       		
  				if (keys.hasOwnProperty(key)) {
  					if (typeof obj[key] !== keys[key])
  					   throw new Error(format(ERROR.INVALID_TYPE, [typeof obj[key], key]));
  				} else {	
  					var errorStr = "Unknown property, " + key + ". Valid properties are:";
  					for (var key in keys)
  						if (keys.hasOwnProperty(key))
  							errorStr = errorStr+" "+key;
  					throw new Error(errorStr);
  				}
  			}
  		}
  	};
  
  	/**
  	 * Return a new function which runs the user function bound
  	 * to a fixed scope. 
  	 * @param {function} User function
  	 * @param {object} Function scope  
  	 * @return {function} User function bound to another scope
  	 * @private 
  	 */
  	var scope = function (f, scope) {
  		return function () {
  			return f.apply(scope, arguments);
  		};
  	};
  	
  	/** 
  	 * Unique message type identifiers, with associated
  	 * associated integer values.
  	 * @private 
  	 */
  	var ERROR = {
  		OK: {code:0, text:"AMQJSC0000I OK."},
  		CONNECT_TIMEOUT: {code:1, text:"AMQJSC0001E Connect timed out."},
  		SUBSCRIBE_TIMEOUT: {code:2, text:"AMQJS0002E Subscribe timed out."}, 
  		UNSUBSCRIBE_TIMEOUT: {code:3, text:"AMQJS0003E Unsubscribe timed out."},
  		PING_TIMEOUT: {code:4, text:"AMQJS0004E Ping timed out."},
  		INTERNAL_ERROR: {code:5, text:"AMQJS0005E Internal error. Error Message: {0}, Stack trace: {1}"},
  		CONNACK_RETURNCODE: {code:6, text:"AMQJS0006E Bad Connack return code:{0} {1}."},
  		SOCKET_ERROR: {code:7, text:"AMQJS0007E Socket error:{0}."},
  		SOCKET_CLOSE: {code:8, text:"AMQJS0008I Socket closed."},
  		MALFORMED_UTF: {code:9, text:"AMQJS0009E Malformed UTF data:{0} {1} {2}."},
  		UNSUPPORTED: {code:10, text:"AMQJS0010E {0} is not supported by this browser."},
  		INVALID_STATE: {code:11, text:"AMQJS0011E Invalid state {0}."},
  		INVALID_TYPE: {code:12, text:"AMQJS0012E Invalid type {0} for {1}."},
  		INVALID_ARGUMENT: {code:13, text:"AMQJS0013E Invalid argument {0} for {1}."},
  		UNSUPPORTED_OPERATION: {code:14, text:"AMQJS0014E Unsupported operation."},
  		INVALID_STORED_DATA: {code:15, text:"AMQJS0015E Invalid data in local storage key={0} value={1}."},
  		INVALID_MQTT_MESSAGE_TYPE: {code:16, text:"AMQJS0016E Invalid MQTT message type {0}."},
  		MALFORMED_UNICODE: {code:17, text:"AMQJS0017E Malformed Unicode string:{0} {1}."},
  	};
  	
  	/** CONNACK RC Meaning. */
  	var CONNACK_RC = {
  		0:"Connection Accepted",
  		1:"Connection Refused: unacceptable protocol version",
  		2:"Connection Refused: identifier rejected",
  		3:"Connection Refused: server unavailable",
  		4:"Connection Refused: bad user name or password",
  		5:"Connection Refused: not authorized"
  	};
  
  	/**
  	 * Format an error message text.
  	 * @private
  	 * @param {error} ERROR.KEY value above.
  	 * @param {substitutions} [array] substituted into the text.
  	 * @return the text with the substitutions made.
  	 */
  	var format = function(error, substitutions) {
  		var text = error.text;
  		if (substitutions) {
  		  var field,start;
  		  for (var i=0; i<substitutions.length; i++) {
  			field = "{"+i+"}";
  			start = text.indexOf(field);
  			if(start > 0) {
  				var part1 = text.substring(0,start);
  				var part2 = text.substring(start+field.length);
  				text = part1+substitutions[i]+part2;
  			}
  		  }
  		}
  		return text;
  	};
  	
  	//MQTT protocol and version          6    M    Q    I    s    d    p    3
  	var MqttProtoIdentifierv3 = [0x00,0x06,0x4d,0x51,0x49,0x73,0x64,0x70,0x03];
  	//MQTT proto/version for 311         4    M    Q    T    T    4
  	var MqttProtoIdentifierv4 = [0x00,0x04,0x4d,0x51,0x54,0x54,0x04];
  	
  	/**
  	 * Construct an MQTT wire protocol message.
  	 * @param type MQTT packet type.
  	 * @param options optional wire message attributes.
  	 * 
  	 * Optional properties
  	 * 
  	 * messageIdentifier: message ID in the range [0..65535]
  	 * payloadMessage:	Application Message - PUBLISH only
  	 * connectStrings:	array of 0 or more Strings to be put into the CONNECT payload
  	 * topics:			array of strings (SUBSCRIBE, UNSUBSCRIBE)
  	 * requestQoS:		array of QoS values [0..2]
  	 *  
  	 * "Flag" properties 
  	 * cleanSession:	true if present / false if absent (CONNECT)
  	 * willMessage:  	true if present / false if absent (CONNECT)
  	 * isRetained:		true if present / false if absent (CONNECT)
  	 * userName:		true if present / false if absent (CONNECT)
  	 * password:		true if present / false if absent (CONNECT)
  	 * keepAliveInterval:	integer [0..65535]  (CONNECT)
  	 *
  	 * @private
  	 * @ignore
  	 */
  	var WireMessage = function (type, options) { 	
  		this.type = type;
  		for (var name in options) {
  			if (options.hasOwnProperty(name)) {
  				this[name] = options[name];
  			}
  		}
  	};
  	
  	WireMessage.prototype.encode = function() {
  		// Compute the first byte of the fixed header
  		var first = ((this.type & 0x0f) << 4);
  		
  		/*
  		 * Now calculate the length of the variable header + payload by adding up the lengths
  		 * of all the component parts
  		 */
  
  		var remLength = 0;
  		var topicStrLength = new Array();
  		var destinationNameLength = 0;
  		
  		// if the message contains a messageIdentifier then we need two bytes for that
  		if (this.messageIdentifier != undefined)
  			remLength += 2;
  
  		switch(this.type) {
  			// If this a Connect then we need to include 12 bytes for its header
  			case MESSAGE_TYPE.CONNECT:
  				switch(this.mqttVersion) {
  					case 3:
  						remLength += MqttProtoIdentifierv3.length + 3;
  						break;
  					case 4:
  						remLength += MqttProtoIdentifierv4.length + 3;
  						break;
  				}
  
  				remLength += UTF8Length(this.clientId) + 2;
  				if (this.willMessage != undefined) {
  					remLength += UTF8Length(this.willMessage.destinationName) + 2;
  					// Will message is always a string, sent as UTF-8 characters with a preceding length.
  					var willMessagePayloadBytes = this.willMessage.payloadBytes;
  					if (!(willMessagePayloadBytes instanceof Uint8Array))
  						willMessagePayloadBytes = new Uint8Array(payloadBytes);
  					remLength += willMessagePayloadBytes.byteLength +2;
  				}
  				if (this.userName != undefined)
  					remLength += UTF8Length(this.userName) + 2;	
  				if (this.password != undefined)
  					remLength += UTF8Length(this.password) + 2;
  			break;
  
  			// Subscribe, Unsubscribe can both contain topic strings
  			case MESSAGE_TYPE.SUBSCRIBE:	        	
  				first |= 0x02; // Qos = 1;
  				for ( var i = 0; i < this.topics.length; i++) {
  					topicStrLength[i] = UTF8Length(this.topics[i]);
  					remLength += topicStrLength[i] + 2;
  				}
  				remLength += this.requestedQos.length; // 1 byte for each topic's Qos
  				// QoS on Subscribe only
  				break;
  
  			case MESSAGE_TYPE.UNSUBSCRIBE:
  				first |= 0x02; // Qos = 1;
  				for ( var i = 0; i < this.topics.length; i++) {
  					topicStrLength[i] = UTF8Length(this.topics[i]);
  					remLength += topicStrLength[i] + 2;
  				}
  				break;
  
  			case MESSAGE_TYPE.PUBREL:
  				first |= 0x02; // Qos = 1;
  				break;
  
  			case MESSAGE_TYPE.PUBLISH:
  				if (this.payloadMessage.duplicate) first |= 0x08;
  				first  = first |= (this.payloadMessage.qos << 1);
  				if (this.payloadMessage.retained) first |= 0x01;
  				destinationNameLength = UTF8Length(this.payloadMessage.destinationName);
  				remLength += destinationNameLength + 2;	   
  				var payloadBytes = this.payloadMessage.payloadBytes;
  				remLength += payloadBytes.byteLength;  
  				if (payloadBytes instanceof ArrayBuffer)
  					payloadBytes = new Uint8Array(payloadBytes);
  				else if (!(payloadBytes instanceof Uint8Array))
  					payloadBytes = new Uint8Array(payloadBytes.buffer);
  				break;
  
  			case MESSAGE_TYPE.DISCONNECT:
  				break;
  
  			default:
  				;
  		}
  
  		// Now we can allocate a buffer for the message
  
  		var mbi = encodeMBI(remLength);  // Convert the length to MQTT MBI format
  		var pos = mbi.length + 1;        // Offset of start of variable header
  		var buffer = new ArrayBuffer(remLength + pos);
  		var byteStream = new Uint8Array(buffer);    // view it as a sequence of bytes
  
  		//Write the fixed header into the buffer
  		byteStream[0] = first;
  		byteStream.set(mbi,1);
  
  		// If this is a PUBLISH then the variable header starts with a topic
  		if (this.type == MESSAGE_TYPE.PUBLISH)
  			pos = writeString(this.payloadMessage.destinationName, destinationNameLength, byteStream, pos);
  		// If this is a CONNECT then the variable header contains the protocol name/version, flags and keepalive time
  		
  		else if (this.type == MESSAGE_TYPE.CONNECT) {
  			switch (this.mqttVersion) {
  				case 3:
  					byteStream.set(MqttProtoIdentifierv3, pos);
  					pos += MqttProtoIdentifierv3.length;
  					break;
  				case 4:
  					byteStream.set(MqttProtoIdentifierv4, pos);
  					pos += MqttProtoIdentifierv4.length;
  					break;
  			}
  			var connectFlags = 0;
  			if (this.cleanSession) 
  				connectFlags = 0x02;
  			if (this.willMessage != undefined ) {
  				connectFlags |= 0x04;
  				connectFlags |= (this.willMessage.qos<<3);
  				if (this.willMessage.retained) {
  					connectFlags |= 0x20;
  				}
  			}
  			if (this.userName != undefined)
  				connectFlags |= 0x80;
  			if (this.password != undefined)
  				connectFlags |= 0x40;
  			byteStream[pos++] = connectFlags; 
  			pos = writeUint16 (this.keepAliveInterval, byteStream, pos);
  		}
  
  		// Output the messageIdentifier - if there is one
  		if (this.messageIdentifier != undefined)
  			pos = writeUint16 (this.messageIdentifier, byteStream, pos);
  
  		switch(this.type) {
  			case MESSAGE_TYPE.CONNECT:
  				pos = writeString(this.clientId, UTF8Length(this.clientId), byteStream, pos); 
  				if (this.willMessage != undefined) {
  					pos = writeString(this.willMessage.destinationName, UTF8Length(this.willMessage.destinationName), byteStream, pos);
  					pos = writeUint16(willMessagePayloadBytes.byteLength, byteStream, pos);
  					byteStream.set(willMessagePayloadBytes, pos);
  					pos += willMessagePayloadBytes.byteLength;
  					
  				}
  			if (this.userName != undefined)
  				pos = writeString(this.userName, UTF8Length(this.userName), byteStream, pos);
  			if (this.password != undefined) 
  				pos = writeString(this.password, UTF8Length(this.password), byteStream, pos);
  			break;
  
  			case MESSAGE_TYPE.PUBLISH:	
  				// PUBLISH has a text or binary payload, if text do not add a 2 byte length field, just the UTF characters.	
  				byteStream.set(payloadBytes, pos);
  					
  				break;
  
  //    	    case MESSAGE_TYPE.PUBREC:	
  //    	    case MESSAGE_TYPE.PUBREL:	
  //    	    case MESSAGE_TYPE.PUBCOMP:	
  //    	    	break;
  
  			case MESSAGE_TYPE.SUBSCRIBE:
  				// SUBSCRIBE has a list of topic strings and request QoS
  				for (var i=0; i<this.topics.length; i++) {
  					pos = writeString(this.topics[i], topicStrLength[i], byteStream, pos);
  					byteStream[pos++] = this.requestedQos[i];
  				}
  				break;
  
  			case MESSAGE_TYPE.UNSUBSCRIBE:	
  				// UNSUBSCRIBE has a list of topic strings
  				for (var i=0; i<this.topics.length; i++)
  					pos = writeString(this.topics[i], topicStrLength[i], byteStream, pos);
  				break;
  
  			default:
  				// Do nothing.
  		}
  
  		return buffer;
  	}	
  
  	function decodeMessage(input,pos) {
  	    var startingPos = pos;
  		var first = input[pos];
  		var type = first >> 4;
  		var messageInfo = first &= 0x0f;
  		pos += 1;
  		
  
  		// Decode the remaining length (MBI format)
  
  		var digit;
  		var remLength = 0;
  		var multiplier = 1;
  		do {
  			if (pos == input.length) {
  			    return [null,startingPos];
  			}
  			digit = input[pos++];
  			remLength += ((digit & 0x7F) * multiplier);
  			multiplier *= 128;
  		} while ((digit & 0x80) != 0);
  		
  		var endPos = pos+remLength;
  		if (endPos > input.length) {
  		    return [null,startingPos];
  		}
  
  		var wireMessage = new WireMessage(type);
  		switch(type) {
  			case MESSAGE_TYPE.CONNACK:
  				var connectAcknowledgeFlags = input[pos++];
  				if (connectAcknowledgeFlags & 0x01)
  					wireMessage.sessionPresent = true;
  				wireMessage.returnCode = input[pos++];
  				break;
  			
  			case MESSAGE_TYPE.PUBLISH:     	    	
  				var qos = (messageInfo >> 1) & 0x03;
  							
  				var len = readUint16(input, pos);
  				pos += 2;
  				var topicName = parseUTF8(input, pos, len);
  				pos += len;
  				// If QoS 1 or 2 there will be a messageIdentifier
  				if (qos > 0) {
  					wireMessage.messageIdentifier = readUint16(input, pos);
  					pos += 2;
  				}
  				
  				var message = new Paho.MQTT.Message(input.subarray(pos, endPos));
  				if ((messageInfo & 0x01) == 0x01) 
  					message.retained = true;
  				if ((messageInfo & 0x08) == 0x08)
  					message.duplicate =  true;
  				message.qos = qos;
  				message.destinationName = topicName;
  				wireMessage.payloadMessage = message;	
  				break;
  			
  			case  MESSAGE_TYPE.PUBACK:
  			case  MESSAGE_TYPE.PUBREC:	    
  			case  MESSAGE_TYPE.PUBREL:    
  			case  MESSAGE_TYPE.PUBCOMP:
  			case  MESSAGE_TYPE.UNSUBACK:    	    	
  				wireMessage.messageIdentifier = readUint16(input, pos);
  				break;
  				
  			case  MESSAGE_TYPE.SUBACK:
  				wireMessage.messageIdentifier = readUint16(input, pos);
  				pos += 2;
  				wireMessage.returnCode = input.subarray(pos, endPos);	
  				break;
  		
  			default:
  				;
  		}
  				
  		return [wireMessage,endPos];	
  	}
  
  	function writeUint16(input, buffer, offset) {
  		buffer[offset++] = input >> 8;      //MSB
  		buffer[offset++] = input % 256;     //LSB 
  		return offset;
  	}	
  
  	function writeString(input, utf8Length, buffer, offset) {
  		offset = writeUint16(utf8Length, buffer, offset);
  		stringToUTF8(input, buffer, offset);
  		return offset + utf8Length;
  	}	
  
  	function readUint16(buffer, offset) {
  		return 256*buffer[offset] + buffer[offset+1];
  	}	
  
  	/**
  	 * Encodes an MQTT Multi-Byte Integer
  	 * @private 
  	 */
  	function encodeMBI(number) {
  		var output = new Array(1);
  		var numBytes = 0;
  
  		do {
  			var digit = number % 128;
  			number = number >> 7;
  			if (number > 0) {
  				digit |= 0x80;
  			}
  			output[numBytes++] = digit;
  		} while ( (number > 0) && (numBytes<4) );
  
  		return output;
  	}
  
  	/**
  	 * Takes a String and calculates its length in bytes when encoded in UTF8.
  	 * @private
  	 */
  	function UTF8Length(input) {
  		var output = 0;
  		for (var i = 0; i<input.length; i++) 
  		{
  			var charCode = input.charCodeAt(i);
  				if (charCode > 0x7FF)
  				   {
  					  // Surrogate pair means its a 4 byte character
  					  if (0xD800 <= charCode && charCode <= 0xDBFF)
  						{
  						  i++;
  						  output++;
  						}
  				   output +=3;
  				   }
  			else if (charCode > 0x7F)
  				output +=2;
  			else
  				output++;
  		} 
  		return output;
  	}
  	
  	/**
  	 * Takes a String and writes it into an array as UTF8 encoded bytes.
  	 * @private
  	 */
  	function stringToUTF8(input, output, start) {
  		var pos = start;
  		for (var i = 0; i<input.length; i++) {
  			var charCode = input.charCodeAt(i);
  			
  			// Check for a surrogate pair.
  			if (0xD800 <= charCode && charCode <= 0xDBFF) {
  				var lowCharCode = input.charCodeAt(++i);
  				if (isNaN(lowCharCode)) {
  					throw new Error(format(ERROR.MALFORMED_UNICODE, [charCode, lowCharCode]));
  				}
  				charCode = ((charCode - 0xD800)<<10) + (lowCharCode - 0xDC00) + 0x10000;
  			
  			}
  			
  			if (charCode <= 0x7F) {
  				output[pos++] = charCode;
  			} else if (charCode <= 0x7FF) {
  				output[pos++] = charCode>>6  & 0x1F | 0xC0;
  				output[pos++] = charCode     & 0x3F | 0x80;
  			} else if (charCode <= 0xFFFF) {    				    
  				output[pos++] = charCode>>12 & 0x0F | 0xE0;
  				output[pos++] = charCode>>6  & 0x3F | 0x80;   
  				output[pos++] = charCode     & 0x3F | 0x80;   
  			} else {
  				output[pos++] = charCode>>18 & 0x07 | 0xF0;
  				output[pos++] = charCode>>12 & 0x3F | 0x80;
  				output[pos++] = charCode>>6  & 0x3F | 0x80;
  				output[pos++] = charCode     & 0x3F | 0x80;
  			};
  		} 
  		return output;
  	}
  	
  	function parseUTF8(input, offset, length) {
  		var output = "";
  		var utf16;
  		var pos = offset;
  
  		while (pos < offset+length)
  		{
  			var byte1 = input[pos++];
  			if (byte1 < 128)
  				utf16 = byte1;
  			else 
  			{
  				var byte2 = input[pos++]-128;
  				if (byte2 < 0) 
  					throw new Error(format(ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16),""]));
  				if (byte1 < 0xE0)             // 2 byte character
  					utf16 = 64*(byte1-0xC0) + byte2;
  				else 
  				{ 
  					var byte3 = input[pos++]-128;
  					if (byte3 < 0) 
  						throw new Error(format(ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16), byte3.toString(16)]));
  					if (byte1 < 0xF0)        // 3 byte character
  						utf16 = 4096*(byte1-0xE0) + 64*byte2 + byte3;
  								else
  								{
  								   var byte4 = input[pos++]-128;
  								   if (byte4 < 0) 
  						throw new Error(format(ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16), byte3.toString(16), byte4.toString(16)]));
  								   if (byte1 < 0xF8)        // 4 byte character 
  										   utf16 = 262144*(byte1-0xF0) + 4096*byte2 + 64*byte3 + byte4;
  					   else                     // longer encodings are not supported  
  						throw new Error(format(ERROR.MALFORMED_UTF, [byte1.toString(16), byte2.toString(16), byte3.toString(16), byte4.toString(16)]));
  								}
  				}
  			}  
  
  				if (utf16 > 0xFFFF)   // 4 byte character - express as a surrogate pair
  				  {
  					 utf16 -= 0x10000;
  					 output += String.fromCharCode(0xD800 + (utf16 >> 10)); // lead character
  					 utf16 = 0xDC00 + (utf16 & 0x3FF);  // trail character
  				  }
  			output += String.fromCharCode(utf16);
  		}
  		return output;
  	}
  	
  	/** 
  	 * Repeat keepalive requests, monitor responses.
  	 * @ignore
  	 */
  	var Pinger = function(client, window, keepAliveInterval) { 
  		this._client = client;        	
  		this._window = window;
  		this._keepAliveInterval = keepAliveInterval*1000;     	
  		this.isReset = false;
  		
  		var pingReq = new WireMessage(MESSAGE_TYPE.PINGREQ).encode(); 
  		
  		var doTimeout = function (pinger) {
  			return function () {
  				return doPing.apply(pinger);
  			};
  		};
  		
  		/** @ignore */
  		var doPing = function() { 
  			if (!this.isReset) {
  				this._client._trace("Pinger.doPing", "Timed out");
  				this._client._disconnected( ERROR.PING_TIMEOUT.code , format(ERROR.PING_TIMEOUT));
  			} else {
  				this.isReset = false;
  				this._client._trace("Pinger.doPing", "send PINGREQ");
  				this._client.socket.send(pingReq); 
  				this.timeout = this._window.setTimeout(doTimeout(this), this._keepAliveInterval);
  			}
  		}
  
  		this.reset = function() {
  			this.isReset = true;
  			this._window.clearTimeout(this.timeout);
  			if (this._keepAliveInterval > 0)
  				this.timeout = setTimeout(doTimeout(this), this._keepAliveInterval);
  		}
  
  		this.cancel = function() {
  			this._window.clearTimeout(this.timeout);
  		}
  	 }; 
  
  	/**
  	 * Monitor request completion.
  	 * @ignore
  	 */
  	var Timeout = function(client, window, timeoutSeconds, action, args) {
  		this._window = window;
  		if (!timeoutSeconds)
  			timeoutSeconds = 30;
  		
  		var doTimeout = function (action, client, args) {
  			return function () {
  				return action.apply(client, args);
  			};
  		};
  		this.timeout = setTimeout(doTimeout(action, client, args), timeoutSeconds * 1000);
  		
  		this.cancel = function() {
  			this._window.clearTimeout(this.timeout);
  		}
  	}; 
  	
  	/*
  	 * Internal implementation of the Websockets MQTT V3.1 client.
  	 * 
  	 * @name Paho.MQTT.ClientImpl @constructor 
  	 * @param {String} host the DNS nameof the webSocket host. 
  	 * @param {Number} port the port number for that host.
  	 * @param {String} clientId the MQ client identifier.
  	 */
  	var ClientImpl = function (uri, host, port, path, clientId) {
  		// Check dependencies are satisfied in this browser.
  		if (!("WebSocket" in global && global["WebSocket"] !== null)) {
  			throw new Error(format(ERROR.UNSUPPORTED, ["WebSocket"]));
  		}
  		if (!("localStorage" in global && global["localStorage"] !== null)) {
  			throw new Error(format(ERROR.UNSUPPORTED, ["localStorage"]));
  		}
  		if (!("ArrayBuffer" in global && global["ArrayBuffer"] !== null)) {
  			throw new Error(format(ERROR.UNSUPPORTED, ["ArrayBuffer"]));
  		}
  		this._trace("Paho.MQTT.Client", uri, host, port, path, clientId);
  
  		this.host = host;
  		this.port = port;
  		this.path = path;
  		this.uri = uri;
  		this.clientId = clientId;
  
  		// Local storagekeys are qualified with the following string.
  		// The conditional inclusion of path in the key is for backward
  		// compatibility to when the path was not configurable and assumed to
  		// be /mqtt
  		this._localKey=host+":"+port+(path!="/mqtt"?":"+path:"")+":"+clientId+":";
  
  		// Create private instance-only message queue
  		// Internal queue of messages to be sent, in sending order. 
  		this._msg_queue = [];
  
  		// Messages we have sent and are expecting a response for, indexed by their respective message ids. 
  		this._sentMessages = {};
  
  		// Messages we have received and acknowleged and are expecting a confirm message for
  		// indexed by their respective message ids. 
  		this._receivedMessages = {};
  
  		// Internal list of callbacks to be executed when messages
  		// have been successfully sent over web socket, e.g. disconnect
  		// when it doesn't have to wait for ACK, just message is dispatched.
  		this._notify_msg_sent = {};
  
  		// Unique identifier for SEND messages, incrementing
  		// counter as messages are sent.
  		this._message_identifier = 1;
  		
  		// Used to determine the transmission sequence of stored sent messages.
  		this._sequence = 0;
  		
  
  		// Load the local state, if any, from the saved version, only restore state relevant to this client.   	
  		for (var key in localStorage)
  			if (   key.indexOf("Sent:"+this._localKey) == 0  		    
  				|| key.indexOf("Received:"+this._localKey) == 0)
  			this.restore(key);
  	};
  
  	// Messaging Client public instance members. 
  	ClientImpl.prototype.host;
  	ClientImpl.prototype.port;
  	ClientImpl.prototype.path;
  	ClientImpl.prototype.uri;
  	ClientImpl.prototype.clientId;
  
  	// Messaging Client private instance members.
  	ClientImpl.prototype.socket;
  	/* true once we have received an acknowledgement to a CONNECT packet. */
  	ClientImpl.prototype.connected = false;
  	/* The largest message identifier allowed, may not be larger than 2**16 but 
  	 * if set smaller reduces the maximum number of outbound messages allowed.
  	 */ 
  	ClientImpl.prototype.maxMessageIdentifier = 65536;
  	ClientImpl.prototype.connectOptions;
  	ClientImpl.prototype.hostIndex;
  	ClientImpl.prototype.onConnectionLost;
  	ClientImpl.prototype.onMessageDelivered;
  	ClientImpl.prototype.onMessageArrived;
  	ClientImpl.prototype.traceFunction;
  	ClientImpl.prototype._msg_queue = null;
  	ClientImpl.prototype._connectTimeout;
  	/* The sendPinger monitors how long we allow before we send data to prove to the server that we are alive. */
  	ClientImpl.prototype.sendPinger = null;
  	/* The receivePinger monitors how long we allow before we require evidence that the server is alive. */
  	ClientImpl.prototype.receivePinger = null;
  	
  	ClientImpl.prototype.receiveBuffer = null;
  	
  	ClientImpl.prototype._traceBuffer = null;
  	ClientImpl.prototype._MAX_TRACE_ENTRIES = 100;
  
  	ClientImpl.prototype.connect = function (connectOptions) {
  		var connectOptionsMasked = this._traceMask(connectOptions, "password"); 
  		this._trace("Client.connect", connectOptionsMasked, this.socket, this.connected);
  		
  		if (this.connected) 
  			throw new Error(format(ERROR.INVALID_STATE, ["already connected"]));
  		if (this.socket)
  			throw new Error(format(ERROR.INVALID_STATE, ["already connected"]));
  		
  		this.connectOptions = connectOptions;
  		
  		if (connectOptions.uris) {
  			this.hostIndex = 0;
  			this._doConnect(connectOptions.uris[0]);  
  		} else {
  			this._doConnect(this.uri);  		
  		}
  		
  	};
  
  	ClientImpl.prototype.subscribe = function (filter, subscribeOptions) {
  		this._trace("Client.subscribe", filter, subscribeOptions);
  			  
  		if (!this.connected)
  			throw new Error(format(ERROR.INVALID_STATE, ["not connected"]));
  		
  		var wireMessage = new WireMessage(MESSAGE_TYPE.SUBSCRIBE);
  		wireMessage.topics=[filter];
  		if (subscribeOptions.qos != undefined)
  			wireMessage.requestedQos = [subscribeOptions.qos];
  		else 
  			wireMessage.requestedQos = [0];
  		
  		if (subscribeOptions.onSuccess) {
  			wireMessage.onSuccess = function(grantedQos) {subscribeOptions.onSuccess({invocationContext:subscribeOptions.invocationContext,grantedQos:grantedQos});};
  		}
  
  		if (subscribeOptions.onFailure) {
  			wireMessage.onFailure = function(errorCode) {subscribeOptions.onFailure({invocationContext:subscribeOptions.invocationContext,errorCode:errorCode});};
  		}
  
  		if (subscribeOptions.timeout) {
  			wireMessage.timeOut = new Timeout(this, window, subscribeOptions.timeout, subscribeOptions.onFailure
  					, [{invocationContext:subscribeOptions.invocationContext, 
  						errorCode:ERROR.SUBSCRIBE_TIMEOUT.code, 
  						errorMessage:format(ERROR.SUBSCRIBE_TIMEOUT)}]);
  		}
  		
  		// All subscriptions return a SUBACK. 
  		this._requires_ack(wireMessage);
  		this._schedule_message(wireMessage);
  	};
  
  	/** @ignore */
  	ClientImpl.prototype.unsubscribe = function(filter, unsubscribeOptions) {  
  		this._trace("Client.unsubscribe", filter, unsubscribeOptions);
  		
  		if (!this.connected)
  		   throw new Error(format(ERROR.INVALID_STATE, ["not connected"]));
  		
  		var wireMessage = new WireMessage(MESSAGE_TYPE.UNSUBSCRIBE);
  		wireMessage.topics = [filter];
  		
  		if (unsubscribeOptions.onSuccess) {
  			wireMessage.callback = function() {unsubscribeOptions.onSuccess({invocationContext:unsubscribeOptions.invocationContext});};
  		}
  		if (unsubscribeOptions.timeout) {
  			wireMessage.timeOut = new Timeout(this, window, unsubscribeOptions.timeout, unsubscribeOptions.onFailure
  					, [{invocationContext:unsubscribeOptions.invocationContext,
  						errorCode:ERROR.UNSUBSCRIBE_TIMEOUT.code,
  						errorMessage:format(ERROR.UNSUBSCRIBE_TIMEOUT)}]);
  		}
  	 
  		// All unsubscribes return a SUBACK.         
  		this._requires_ack(wireMessage);
  		this._schedule_message(wireMessage);
  	};
  	 
  	ClientImpl.prototype.send = function (message) {
  		this._trace("Client.send", message);
  
  		if (!this.connected)
  		   throw new Error(format(ERROR.INVALID_STATE, ["not connected"]));
  		
  		wireMessage = new WireMessage(MESSAGE_TYPE.PUBLISH);
  		wireMessage.payloadMessage = message;
  		
  		if (message.qos > 0)
  			this._requires_ack(wireMessage);
  		else if (this.onMessageDelivered)
  			this._notify_msg_sent[wireMessage] = this.onMessageDelivered(wireMessage.payloadMessage);
  		this._schedule_message(wireMessage);
  	};
  	
  	ClientImpl.prototype.disconnect = function () {
  		this._trace("Client.disconnect");
  
  		if (!this.socket)
  			throw new Error(format(ERROR.INVALID_STATE, ["not connecting or connected"]));
  		
  		wireMessage = new WireMessage(MESSAGE_TYPE.DISCONNECT);
  
  		// Run the disconnected call back as soon as the message has been sent,
  		// in case of a failure later on in the disconnect processing.
  		// as a consequence, the _disconected call back may be run several times.
  		this._notify_msg_sent[wireMessage] = scope(this._disconnected, this);
  
  		this._schedule_message(wireMessage);
  	};
  	
  	ClientImpl.prototype.getTraceLog = function () {
  		if ( this._traceBuffer !== null ) {
  			this._trace("Client.getTraceLog", new Date());
  			this._trace("Client.getTraceLog in flight messages", this._sentMessages.length);
  			for (var key in this._sentMessages)
  				this._trace("_sentMessages ",key, this._sentMessages[key]);
  			for (var key in this._receivedMessages)
  				this._trace("_receivedMessages ",key, this._receivedMessages[key]);
  			
  			return this._traceBuffer;
  		}
  	};
  	
  	ClientImpl.prototype.startTrace = function () {
  		if ( this._traceBuffer === null ) {
  			this._traceBuffer = [];
  		}
  		this._trace("Client.startTrace", new Date(), version);
  	};
  	
  	ClientImpl.prototype.stopTrace = function () {
  		delete this._traceBuffer;
  	};
  
  	ClientImpl.prototype._doConnect = function (wsurl) { 	        
  		// When the socket is open, this client will send the CONNECT WireMessage using the saved parameters. 
  		if (this.connectOptions.useSSL) {
  		    var uriParts = wsurl.split(":");
  		    uriParts[0] = "wss";
  		    wsurl = uriParts.join(":");
  		}
  		this.connected = false;
  		if (this.connectOptions.mqttVersion < 4) {
  			this.socket = new WebSocket(wsurl, ["mqttv3.1"]);
  		} else {
  			this.socket = new WebSocket(wsurl, ["mqtt"]);
  		}
  		this.socket.binaryType = 'arraybuffer';
  		
  		this.socket.onopen = scope(this._on_socket_open, this);
  		this.socket.onmessage = scope(this._on_socket_message, this);
  		this.socket.onerror = scope(this._on_socket_error, this);
  		this.socket.onclose = scope(this._on_socket_close, this);
  		
  		this.sendPinger = new Pinger(this, window, this.connectOptions.keepAliveInterval);
  		this.receivePinger = new Pinger(this, window, this.connectOptions.keepAliveInterval);
  		
  		this._connectTimeout = new Timeout(this, window, this.connectOptions.timeout, this._disconnected,  [ERROR.CONNECT_TIMEOUT.code, format(ERROR.CONNECT_TIMEOUT)]);
  	};
  
  	
  	// Schedule a new message to be sent over the WebSockets
  	// connection. CONNECT messages cause WebSocket connection
  	// to be started. All other messages are queued internally
  	// until this has happened. When WS connection starts, process
  	// all outstanding messages. 
  	ClientImpl.prototype._schedule_message = function (message) {
  		this._msg_queue.push(message);
  		// Process outstanding messages in the queue if we have an  open socket, and have received CONNACK. 
  		if (this.connected) {
  			this._process_queue();
  		}
  	};
  
  	ClientImpl.prototype.store = function(prefix, wireMessage) {
  		var storedMessage = {type:wireMessage.type, messageIdentifier:wireMessage.messageIdentifier, version:1};
  		
  		switch(wireMessage.type) {
  		  case MESSAGE_TYPE.PUBLISH:
  			  if(wireMessage.pubRecReceived)
  				  storedMessage.pubRecReceived = true;
  			  
  			  // Convert the payload to a hex string.
  			  storedMessage.payloadMessage = {};
  			  var hex = "";
  			  var messageBytes = wireMessage.payloadMessage.payloadBytes;
  			  for (var i=0; i<messageBytes.length; i++) {
  				if (messageBytes[i] <= 0xF)
  				  hex = hex+"0"+messageBytes[i].toString(16);
  				else 
  				  hex = hex+messageBytes[i].toString(16);
  			  }
  			  storedMessage.payloadMessage.payloadHex = hex;
  			  
  			  storedMessage.payloadMessage.qos = wireMessage.payloadMessage.qos;
  			  storedMessage.payloadMessage.destinationName = wireMessage.payloadMessage.destinationName;
  			  if (wireMessage.payloadMessage.duplicate) 
  				  storedMessage.payloadMessage.duplicate = true;
  			  if (wireMessage.payloadMessage.retained) 
  				  storedMessage.payloadMessage.retained = true;	   
  			  
  			  // Add a sequence number to sent messages.
  			  if ( prefix.indexOf("Sent:") == 0 ) {
  				  if ( wireMessage.sequence === undefined )
  					  wireMessage.sequence = ++this._sequence;
  				  storedMessage.sequence = wireMessage.sequence;
  			  }
  			  break;    
  			  
  			default:
  				throw Error(format(ERROR.INVALID_STORED_DATA, [key, storedMessage]));
  		}
  		localStorage.setItem(prefix+this._localKey+wireMessage.messageIdentifier, JSON.stringify(storedMessage));
  	};
  	
  	ClientImpl.prototype.restore = function(key) {    	
  		var value = localStorage.getItem(key);
  		var storedMessage = JSON.parse(value);
  		
  		var wireMessage = new WireMessage(storedMessage.type, storedMessage);
  		
  		switch(storedMessage.type) {
  		  case MESSAGE_TYPE.PUBLISH:
  			  // Replace the payload message with a Message object.
  			  var hex = storedMessage.payloadMessage.payloadHex;
  			  var buffer = new ArrayBuffer((hex.length)/2);
  			  var byteStream = new Uint8Array(buffer); 
  			  var i = 0;
  			  while (hex.length >= 2) { 
  				  var x = parseInt(hex.substring(0, 2), 16);
  				  hex = hex.substring(2, hex.length);
  				  byteStream[i++] = x;
  			  }
  			  var payloadMessage = new Paho.MQTT.Message(byteStream);
  			  
  			  payloadMessage.qos = storedMessage.payloadMessage.qos;
  			  payloadMessage.destinationName = storedMessage.payloadMessage.destinationName;
  			  if (storedMessage.payloadMessage.duplicate) 
  				  payloadMessage.duplicate = true;
  			  if (storedMessage.payloadMessage.retained) 
  				  payloadMessage.retained = true;	 
  			  wireMessage.payloadMessage = payloadMessage;
  			  
  			  break;    
  			  
  			default:
  			  throw Error(format(ERROR.INVALID_STORED_DATA, [key, value]));
  		}
  							
  		if (key.indexOf("Sent:"+this._localKey) == 0) {
  			wireMessage.payloadMessage.duplicate = true;
  			this._sentMessages[wireMessage.messageIdentifier] = wireMessage;    		    
  		} else if (key.indexOf("Received:"+this._localKey) == 0) {
  			this._receivedMessages[wireMessage.messageIdentifier] = wireMessage;
  		}
  	};
  	
  	ClientImpl.prototype._process_queue = function () {
  		var message = null;
  		// Process messages in order they were added
  		var fifo = this._msg_queue.reverse();
  
  		// Send all queued messages down socket connection
  		while ((message = fifo.pop())) {
  			this._socket_send(message);
  			// Notify listeners that message was successfully sent
  			if (this._notify_msg_sent[message]) {
  				this._notify_msg_sent[message]();
  				delete this._notify_msg_sent[message];
  			}
  		}
  	};
  
  	/**
  	 * Expect an ACK response for this message. Add message to the set of in progress
  	 * messages and set an unused identifier in this message.
  	 * @ignore
  	 */
  	ClientImpl.prototype._requires_ack = function (wireMessage) {
  		var messageCount = Object.keys(this._sentMessages).length;
  		if (messageCount > this.maxMessageIdentifier)
  			throw Error ("Too many messages:"+messageCount);
  
  		while(this._sentMessages[this._message_identifier] !== undefined) {
  			this._message_identifier++;
  		}
  		wireMessage.messageIdentifier = this._message_identifier;
  		this._sentMessages[wireMessage.messageIdentifier] = wireMessage;
  		if (wireMessage.type === MESSAGE_TYPE.PUBLISH) {
  			this.store("Sent:", wireMessage);
  		}
  		if (this._message_identifier === this.maxMessageIdentifier) {
  			this._message_identifier = 1;
  		}
  	};
  
  	/** 
  	 * Called when the underlying websocket has been opened.
  	 * @ignore
  	 */
  	ClientImpl.prototype._on_socket_open = function () {      
  		// Create the CONNECT message object.
  		var wireMessage = new WireMessage(MESSAGE_TYPE.CONNECT, this.connectOptions); 
  		wireMessage.clientId = this.clientId;
  		this._socket_send(wireMessage);
  	};
  
  	/** 
  	 * Called when the underlying websocket has received a complete packet.
  	 * @ignore
  	 */
  	ClientImpl.prototype._on_socket_message = function (event) {
  		this._trace("Client._on_socket_message", event.data);
  		// Reset the receive ping timer, we now have evidence the server is alive.
  		this.receivePinger.reset();
  		var messages = this._deframeMessages(event.data);
  		for (var i = 0; i < messages.length; i+=1) {
  		    this._handleMessage(messages[i]);
  		}
  	}
  	
  	ClientImpl.prototype._deframeMessages = function(data) {
  		var byteArray = new Uint8Array(data);
  	    if (this.receiveBuffer) {
  	        var newData = new Uint8Array(this.receiveBuffer.length+byteArray.length);
  	        newData.set(this.receiveBuffer);
  	        newData.set(byteArray,this.receiveBuffer.length);
  	        byteArray = newData;
  	        delete this.receiveBuffer;
  	    }
  		try {
  		    var offset = 0;
  		    var messages = [];
  		    while(offset < byteArray.length) {
  		        var result = decodeMessage(byteArray,offset);
  		        var wireMessage = result[0];
  		        offset = result[1];
  		        if (wireMessage !== null) {
  		            messages.push(wireMessage);
  		        } else {
  		            break;
  		        }
  		    }
  		    if (offset < byteArray.length) {
  		    	this.receiveBuffer = byteArray.subarray(offset);
  		    }
  		} catch (error) {
  			this._disconnected(ERROR.INTERNAL_ERROR.code , format(ERROR.INTERNAL_ERROR, [error.message,error.stack.toString()]));
  			return;
  		}
  		return messages;
  	}
  	
  	ClientImpl.prototype._handleMessage = function(wireMessage) {
  		
  		this._trace("Client._handleMessage", wireMessage);
  
  		try {
  			switch(wireMessage.type) {
  			case MESSAGE_TYPE.CONNACK:
  				this._connectTimeout.cancel();
  				
  				// If we have started using clean session then clear up the local state.
  				if (this.connectOptions.cleanSession) {
  					for (var key in this._sentMessages) {	    		
  						var sentMessage = this._sentMessages[key];
  						localStorage.removeItem("Sent:"+this._localKey+sentMessage.messageIdentifier);
  					}
  					this._sentMessages = {};
  
  					for (var key in this._receivedMessages) {
  						var receivedMessage = this._receivedMessages[key];
  						localStorage.removeItem("Received:"+this._localKey+receivedMessage.messageIdentifier);
  					}
  					this._receivedMessages = {};
  				}
  				// Client connected and ready for business.
  				if (wireMessage.returnCode === 0) {
  					this.connected = true;
  					// Jump to the end of the list of uris and stop looking for a good host.
  					if (this.connectOptions.uris)
  						this.hostIndex = this.connectOptions.uris.length;
  				} else {
  					this._disconnected(ERROR.CONNACK_RETURNCODE.code , format(ERROR.CONNACK_RETURNCODE, [wireMessage.returnCode, CONNACK_RC[wireMessage.returnCode]]));
  					break;
  				}
  				
  				// Resend messages.
  				var sequencedMessages = new Array();
  				for (var msgId in this._sentMessages) {
  					if (this._sentMessages.hasOwnProperty(msgId))
  						sequencedMessages.push(this._sentMessages[msgId]);
  				}
  		  
  				// Sort sentMessages into the original sent order.
  				var sequencedMessages = sequencedMessages.sort(function(a,b) {return a.sequence - b.sequence;} );
  				for (var i=0, len=sequencedMessages.length; i<len; i++) {
  					var sentMessage = sequencedMessages[i];
  					if (sentMessage.type == MESSAGE_TYPE.PUBLISH && sentMessage.pubRecReceived) {
  						var pubRelMessage = new WireMessage(MESSAGE_TYPE.PUBREL, {messageIdentifier:sentMessage.messageIdentifier});
  						this._schedule_message(pubRelMessage);
  					} else {
  						this._schedule_message(sentMessage);
  					};
  				}
  
  				// Execute the connectOptions.onSuccess callback if there is one.
  				if (this.connectOptions.onSuccess) {
  					this.connectOptions.onSuccess({invocationContext:this.connectOptions.invocationContext});
  				}
  
  				// Process all queued messages now that the connection is established. 
  				this._process_queue();
  				break;
  		
  			case MESSAGE_TYPE.PUBLISH:
  				this._receivePublish(wireMessage);
  				break;
  
  			case MESSAGE_TYPE.PUBACK:
  				var sentMessage = this._sentMessages[wireMessage.messageIdentifier];
  				 // If this is a re flow of a PUBACK after we have restarted receivedMessage will not exist.
  				if (sentMessage) {
  					delete this._sentMessages[wireMessage.messageIdentifier];
  					localStorage.removeItem("Sent:"+this._localKey+wireMessage.messageIdentifier);
  					if (this.onMessageDelivered)
  						this.onMessageDelivered(sentMessage.payloadMessage);
  				}
  				break;
  			
  			case MESSAGE_TYPE.PUBREC:
  				var sentMessage = this._sentMessages[wireMessage.messageIdentifier];
  				// If this is a re flow of a PUBREC after we have restarted receivedMessage will not exist.
  				if (sentMessage) {
  					sentMessage.pubRecReceived = true;
  					var pubRelMessage = new WireMessage(MESSAGE_TYPE.PUBREL, {messageIdentifier:wireMessage.messageIdentifier});
  					this.store("Sent:", sentMessage);
  					this._schedule_message(pubRelMessage);
  				}
  				break;
  								
  			case MESSAGE_TYPE.PUBREL:
  				var receivedMessage = this._receivedMessages[wireMessage.messageIdentifier];
  				localStorage.removeItem("Received:"+this._localKey+wireMessage.messageIdentifier);
  				// If this is a re flow of a PUBREL after we have restarted receivedMessage will not exist.
  				if (receivedMessage) {
  					this._receiveMessage(receivedMessage);
  					delete this._receivedMessages[wireMessage.messageIdentifier];
  				}
  				// Always flow PubComp, we may have previously flowed PubComp but the server lost it and restarted.
  				var pubCompMessage = new WireMessage(MESSAGE_TYPE.PUBCOMP, {messageIdentifier:wireMessage.messageIdentifier});
  				this._schedule_message(pubCompMessage);                    
  				break;
  
  			case MESSAGE_TYPE.PUBCOMP: 
  				var sentMessage = this._sentMessages[wireMessage.messageIdentifier];
  				delete this._sentMessages[wireMessage.messageIdentifier];
  				localStorage.removeItem("Sent:"+this._localKey+wireMessage.messageIdentifier);
  				if (this.onMessageDelivered)
  					this.onMessageDelivered(sentMessage.payloadMessage);
  				break;
  				
  			case MESSAGE_TYPE.SUBACK:
  				var sentMessage = this._sentMessages[wireMessage.messageIdentifier];
  				if (sentMessage) {
  					if(sentMessage.timeOut)
  						sentMessage.timeOut.cancel();
  					wireMessage.returnCode.indexOf = Array.prototype.indexOf;
  					if (wireMessage.returnCode.indexOf(0x80) !== -1) {
  						if (sentMessage.onFailure) {
  							sentMessage.onFailure(wireMessage.returnCode);
  						} 
  					} else if (sentMessage.onSuccess) {
  						sentMessage.onSuccess(wireMessage.returnCode);
  					}
  					delete this._sentMessages[wireMessage.messageIdentifier];
  				}
  				break;
  				
  			case MESSAGE_TYPE.UNSUBACK:
  				var sentMessage = this._sentMessages[wireMessage.messageIdentifier];
  				if (sentMessage) { 
  					if (sentMessage.timeOut)
  						sentMessage.timeOut.cancel();
  					if (sentMessage.callback) {
  						sentMessage.callback();
  					}
  					delete this._sentMessages[wireMessage.messageIdentifier];
  				}
  
  				break;
  				
  			case MESSAGE_TYPE.PINGRESP:
  				/* The sendPinger or receivePinger may have sent a ping, the receivePinger has already been reset. */
  				this.sendPinger.reset();
  				break;
  				
  			case MESSAGE_TYPE.DISCONNECT:
  				// Clients do not expect to receive disconnect packets.
  				this._disconnected(ERROR.INVALID_MQTT_MESSAGE_TYPE.code , format(ERROR.INVALID_MQTT_MESSAGE_TYPE, [wireMessage.type]));
  				break;
  
  			default:
  				this._disconnected(ERROR.INVALID_MQTT_MESSAGE_TYPE.code , format(ERROR.INVALID_MQTT_MESSAGE_TYPE, [wireMessage.type]));
  			};
  		} catch (error) {
  			this._disconnected(ERROR.INTERNAL_ERROR.code , format(ERROR.INTERNAL_ERROR, [error.message,error.stack.toString()]));
  			return;
  		}
  	};
  	
  	/** @ignore */
  	ClientImpl.prototype._on_socket_error = function (error) {
  		this._disconnected(ERROR.SOCKET_ERROR.code , format(ERROR.SOCKET_ERROR, [error.data]));
  	};
  
  	/** @ignore */
  	ClientImpl.prototype._on_socket_close = function () {
  		this._disconnected(ERROR.SOCKET_CLOSE.code , format(ERROR.SOCKET_CLOSE));
  	};
  
  	/** @ignore */
  	ClientImpl.prototype._socket_send = function (wireMessage) {
  		
  		if (wireMessage.type == 1) {
  			var wireMessageMasked = this._traceMask(wireMessage, "password"); 
  			this._trace("Client._socket_send", wireMessageMasked);
  		}
  		else this._trace("Client._socket_send", wireMessage);
  		
  		this.socket.send(wireMessage.encode());
  		/* We have proved to the server we are alive. */
  		this.sendPinger.reset();
  	};
  	
  	/** @ignore */
  	ClientImpl.prototype._receivePublish = function (wireMessage) {
  		switch(wireMessage.payloadMessage.qos) {
  			case "undefined":
  			case 0:
  				this._receiveMessage(wireMessage);
  				break;
  
  			case 1:
  				var pubAckMessage = new WireMessage(MESSAGE_TYPE.PUBACK, {messageIdentifier:wireMessage.messageIdentifier});
  				this._schedule_message(pubAckMessage);
  				this._receiveMessage(wireMessage);
  				break;
  
  			case 2:
  				this._receivedMessages[wireMessage.messageIdentifier] = wireMessage;
  				this.store("Received:", wireMessage);
  				var pubRecMessage = new WireMessage(MESSAGE_TYPE.PUBREC, {messageIdentifier:wireMessage.messageIdentifier});
  				this._schedule_message(pubRecMessage);
  
  				break;
  
  			default:
  				throw Error("Invaild qos="+wireMmessage.payloadMessage.qos);
  		};
  	};
  
  	/** @ignore */
  	ClientImpl.prototype._receiveMessage = function (wireMessage) {
  		if (this.onMessageArrived) {
  			this.onMessageArrived(wireMessage.payloadMessage);
  		}
  	};
  
  	/**
  	 * Client has disconnected either at its own request or because the server
  	 * or network disconnected it. Remove all non-durable state.
  	 * @param {errorCode} [number] the error number.
  	 * @param {errorText} [string] the error text.
  	 * @ignore
  	 */
  	ClientImpl.prototype._disconnected = function (errorCode, errorText) {
  		this._trace("Client._disconnected", errorCode, errorText);
  		
  		this.sendPinger.cancel();
  		this.receivePinger.cancel();
  		if (this._connectTimeout)
  			this._connectTimeout.cancel();
  		// Clear message buffers.
  		this._msg_queue = [];
  		this._notify_msg_sent = {};
  	   
  		if (this.socket) {
  			// Cancel all socket callbacks so that they cannot be driven again by this socket.
  			this.socket.onopen = null;
  			this.socket.onmessage = null;
  			this.socket.onerror = null;
  			this.socket.onclose = null;
  			if (this.socket.readyState === 1)
  				this.socket.close();
  			delete this.socket;           
  		}
  		
  		if (this.connectOptions.uris && this.hostIndex < this.connectOptions.uris.length-1) {
  			// Try the next host.
  			this.hostIndex++;
  			this._doConnect(this.connectOptions.uris[this.hostIndex]);
  		
  		} else {
  		
  			if (errorCode === undefined) {
  				errorCode = ERROR.OK.code;
  				errorText = format(ERROR.OK);
  			}
  			
  			// Run any application callbacks last as they may attempt to reconnect and hence create a new socket.
  			if (this.connected) {
  				this.connected = false;
  				// Execute the connectionLostCallback if there is one, and we were connected.       
  				if (this.onConnectionLost)
  					this.onConnectionLost({errorCode:errorCode, errorMessage:errorText});      	
  			} else {
  				// Otherwise we never had a connection, so indicate that the connect has failed.
  				if (this.connectOptions.mqttVersion === 4 && this.connectOptions.mqttVersionExplicit === false) {
  					this._trace("Failed to connect V4, dropping back to V3")
  					this.connectOptions.mqttVersion = 3;
  					if (this.connectOptions.uris) {
  						this.hostIndex = 0;
  						this._doConnect(this.connectOptions.uris[0]);  
  					} else {
  						this._doConnect(this.uri);
  					}	
  				} else if(this.connectOptions.onFailure) {
  					this.connectOptions.onFailure({invocationContext:this.connectOptions.invocationContext, errorCode:errorCode, errorMessage:errorText});
  				}
  			}
  		}
  	};
  
  	/** @ignore */
  	ClientImpl.prototype._trace = function () {
  		// Pass trace message back to client's callback function
  		if (this.traceFunction) {
  			for (var i in arguments)
  			{	
  				if (typeof arguments[i] !== "undefined")
  					arguments[i] = JSON.stringify(arguments[i]);
  			}
  			var record = Array.prototype.slice.call(arguments).join("");
  			this.traceFunction ({severity: "Debug", message: record	});
  		}
  
  		//buffer style trace
  		if ( this._traceBuffer !== null ) {  
  			for (var i = 0, max = arguments.length; i < max; i++) {
  				if ( this._traceBuffer.length == this._MAX_TRACE_ENTRIES ) {    
  					this._traceBuffer.shift();              
  				}
  				if (i === 0) this._traceBuffer.push(arguments[i]);
  				else if (typeof arguments[i] === "undefined" ) this._traceBuffer.push(arguments[i]);
  				else this._traceBuffer.push("  "+JSON.stringify(arguments[i]));
  		   };
  		};
  	};
  	
  	/** @ignore */
  	ClientImpl.prototype._traceMask = function (traceObject, masked) {
  		var traceObjectMasked = {};
  		for (var attr in traceObject) {
  			if (traceObject.hasOwnProperty(attr)) {
  				if (attr == masked) 
  					traceObjectMasked[attr] = "******";
  				else
  					traceObjectMasked[attr] = traceObject[attr];
  			} 
  		}
  		return traceObjectMasked;
  	};
  
  	// ------------------------------------------------------------------------
  	// Public Programming interface.
  	// ------------------------------------------------------------------------
  	
  	/** 
  	 * The JavaScript application communicates to the server using a {@link Paho.MQTT.Client} object. 
  	 * <p>
  	 * Most applications will create just one Client object and then call its connect() method,
  	 * however applications can create more than one Client object if they wish. 
  	 * In this case the combination of host, port and clientId attributes must be different for each Client object.
  	 * <p>
  	 * The send, subscribe and unsubscribe methods are implemented as asynchronous JavaScript methods 
  	 * (even though the underlying protocol exchange might be synchronous in nature). 
  	 * This means they signal their completion by calling back to the application, 
  	 * via Success or Failure callback functions provided by the application on the method in question. 
  	 * Such callbacks are called at most once per method invocation and do not persist beyond the lifetime 
  	 * of the script that made the invocation.
  	 * <p>
  	 * In contrast there are some callback functions, most notably <i>onMessageArrived</i>, 
  	 * that are defined on the {@link Paho.MQTT.Client} object.  
  	 * These may get called multiple times, and aren't directly related to specific method invocations made by the client. 
  	 *
  	 * @name Paho.MQTT.Client    
  	 * 
  	 * @constructor
  	 *  
  	 * @param {string} host - the address of the messaging server, as a fully qualified WebSocket URI, as a DNS name or dotted decimal IP address.
  	 * @param {number} port - the port number to connect to - only required if host is not a URI
  	 * @param {string} path - the path on the host to connect to - only used if host is not a URI. Default: '/mqtt'.
  	 * @param {string} clientId - the Messaging client identifier, between 1 and 23 characters in length.
  	 * 
  	 * @property {string} host - <i>read only</i> the server's DNS hostname or dotted decimal IP address.
  	 * @property {number} port - <i>read only</i> the server's port.
  	 * @property {string} path - <i>read only</i> the server's path.
  	 * @property {string} clientId - <i>read only</i> used when connecting to the server.
  	 * @property {function} onConnectionLost - called when a connection has been lost. 
  	 *                            after a connect() method has succeeded.
  	 *                            Establish the call back used when a connection has been lost. The connection may be
  	 *                            lost because the client initiates a disconnect or because the server or network 
  	 *                            cause the client to be disconnected. The disconnect call back may be called without 
  	 *                            the connectionComplete call back being invoked if, for example the client fails to 
  	 *                            connect.
  	 *                            A single response object parameter is passed to the onConnectionLost callback containing the following fields:
  	 *                            <ol>   
  	 *                            <li>errorCode
  	 *                            <li>errorMessage       
  	 *                            </ol>
  	 * @property {function} onMessageDelivered called when a message has been delivered. 
  	 *                            All processing that this Client will ever do has been completed. So, for example,
  	 *                            in the case of a Qos=2 message sent by this client, the PubComp flow has been received from the server
  	 *                            and the message has been removed from persistent storage before this callback is invoked. 
  	 *                            Parameters passed to the onMessageDelivered callback are:
  	 *                            <ol>   
  	 *                            <li>{@link Paho.MQTT.Message} that was delivered.
  	 *                            </ol>    
  	 * @property {function} onMessageArrived called when a message has arrived in this Paho.MQTT.client. 
  	 *                            Parameters passed to the onMessageArrived callback are:
  	 *                            <ol>   
  	 *                            <li>{@link Paho.MQTT.Message} that has arrived.
  	 *                            </ol>    
  	 */
  	var Client = function (host, port, path, clientId) {
  	    
  	    var uri;
  	    
  		if (typeof host !== "string")
  			throw new Error(format(ERROR.INVALID_TYPE, [typeof host, "host"]));
  	    
  	    if (arguments.length == 2) {
  	        // host: must be full ws:// uri
  	        // port: clientId
  	        clientId = port;
  	        uri = host;
  	        var match = uri.match(/^(wss?):\/\/((\[(.+)\])|([^\/]+?))(:(\d+))?(\/.*)$/);
  	        if (match) {
  	            host = match[4]||match[2];
  	            port = parseInt(match[7]);
  	            path = match[8];
  	        } else {
  	            throw new Error(format(ERROR.INVALID_ARGUMENT,[host,"host"]));
  	        }
  	    } else {
  	        if (arguments.length == 3) {
  				clientId = path;
  				path = "/mqtt";
  			}
  			if (typeof port !== "number" || port < 0)
  				throw new Error(format(ERROR.INVALID_TYPE, [typeof port, "port"]));
  			if (typeof path !== "string")
  				throw new Error(format(ERROR.INVALID_TYPE, [typeof path, "path"]));
  			
  			var ipv6AddSBracket = (host.indexOf(":") != -1 && host.slice(0,1) != "[" && host.slice(-1) != "]");
  			uri = "ws://"+(ipv6AddSBracket?"["+host+"]":host)+":"+port+path;
  		}
  
  		var clientIdLength = 0;
  		for (var i = 0; i<clientId.length; i++) {
  			var charCode = clientId.charCodeAt(i);                   
  			if (0xD800 <= charCode && charCode <= 0xDBFF)  {    			
  				 i++; // Surrogate pair.
  			}   		   
  			clientIdLength++;
  		}     	   	
  		if (typeof clientId !== "string" || clientIdLength > 65535)
  			throw new Error(format(ERROR.INVALID_ARGUMENT, [clientId, "clientId"])); 
  		
  		var client = new ClientImpl(uri, host, port, path, clientId);
  		this._getHost =  function() { return host; };
  		this._setHost = function() { throw new Error(format(ERROR.UNSUPPORTED_OPERATION)); };
  			
  		this._getPort = function() { return port; };
  		this._setPort = function() { throw new Error(format(ERROR.UNSUPPORTED_OPERATION)); };
  
  		this._getPath = function() { return path; };
  		this._setPath = function() { throw new Error(format(ERROR.UNSUPPORTED_OPERATION)); };
  
  		this._getURI = function() { return uri; };
  		this._setURI = function() { throw new Error(format(ERROR.UNSUPPORTED_OPERATION)); };
  		
  		this._getClientId = function() { return client.clientId; };
  		this._setClientId = function() { throw new Error(format(ERROR.UNSUPPORTED_OPERATION)); };
  		
  		this._getOnConnectionLost = function() { return client.onConnectionLost; };
  		this._setOnConnectionLost = function(newOnConnectionLost) { 
  			if (typeof newOnConnectionLost === "function")
  				client.onConnectionLost = newOnConnectionLost;
  			else 
  				throw new Error(format(ERROR.INVALID_TYPE, [typeof newOnConnectionLost, "onConnectionLost"]));
  		};
  
  		this._getOnMessageDelivered = function() { return client.onMessageDelivered; };
  		this._setOnMessageDelivered = function(newOnMessageDelivered) { 
  			if (typeof newOnMessageDelivered === "function")
  				client.onMessageDelivered = newOnMessageDelivered;
  			else 
  				throw new Error(format(ERROR.INVALID_TYPE, [typeof newOnMessageDelivered, "onMessageDelivered"]));
  		};
  	   
  		this._getOnMessageArrived = function() { return client.onMessageArrived; };
  		this._setOnMessageArrived = function(newOnMessageArrived) { 
  			if (typeof newOnMessageArrived === "function")
  				client.onMessageArrived = newOnMessageArrived;
  			else 
  				throw new Error(format(ERROR.INVALID_TYPE, [typeof newOnMessageArrived, "onMessageArrived"]));
  		};
  
  		this._getTrace = function() { return client.traceFunction; };
  		this._setTrace = function(trace) {
  			if(typeof trace === "function"){
  				client.traceFunction = trace;
  			}else{
  				throw new Error(format(ERROR.INVALID_TYPE, [typeof trace, "onTrace"]));
  			}
  		};
  		
  		/** 
  		 * Connect this Messaging client to its server. 
  		 * 
  		 * @name Paho.MQTT.Client#connect
  		 * @function
  		 * @param {Object} connectOptions - attributes used with the connection. 
  		 * @param {number} connectOptions.timeout - If the connect has not succeeded within this 
  		 *                    number of seconds, it is deemed to have failed.
  		 *                    The default is 30 seconds.
  		 * @param {string} connectOptions.userName - Authentication username for this connection.
  		 * @param {string} connectOptions.password - Authentication password for this connection.
  		 * @param {Paho.MQTT.Message} connectOptions.willMessage - sent by the server when the client
  		 *                    disconnects abnormally.
  		 * @param {Number} connectOptions.keepAliveInterval - the server disconnects this client if
  		 *                    there is no activity for this number of seconds.
  		 *                    The default value of 60 seconds is assumed if not set.
  		 * @param {boolean} connectOptions.cleanSession - if true(default) the client and server 
  		 *                    persistent state is deleted on successful connect.
  		 * @param {boolean} connectOptions.useSSL - if present and true, use an SSL Websocket connection.
  		 * @param {object} connectOptions.invocationContext - passed to the onSuccess callback or onFailure callback.
  		 * @param {function} connectOptions.onSuccess - called when the connect acknowledgement 
  		 *                    has been received from the server.
  		 * A single response object parameter is passed to the onSuccess callback containing the following fields:
  		 * <ol>
  		 * <li>invocationContext as passed in to the onSuccess method in the connectOptions.       
  		 * </ol>
  		 * @config {function} [onFailure] called when the connect request has failed or timed out.
  		 * A single response object parameter is passed to the onFailure callback containing the following fields:
  		 * <ol>
  		 * <li>invocationContext as passed in to the onFailure method in the connectOptions.       
  		 * <li>errorCode a number indicating the nature of the error.
  		 * <li>errorMessage text describing the error.      
  		 * </ol>
  		 * @config {Array} [hosts] If present this contains either a set of hostnames or fully qualified
  		 * WebSocket URIs (ws://example.com:1883/mqtt), that are tried in order in place 
  		 * of the host and port paramater on the construtor. The hosts are tried one at at time in order until
  		 * one of then succeeds.
  		 * @config {Array} [ports] If present the set of ports matching the hosts. If hosts contains URIs, this property
  		 * is not used.
  		 * @throws {InvalidState} if the client is not in disconnected state. The client must have received connectionLost
  		 * or disconnected before calling connect for a second or subsequent time.
  		 */
  		this.connect = function (connectOptions) {
  			connectOptions = connectOptions || {} ;
  			validate(connectOptions,  {timeout:"number",
  									   userName:"string", 
  									   password:"string", 
  									   willMessage:"object", 
  									   keepAliveInterval:"number", 
  									   cleanSession:"boolean", 
  									   useSSL:"boolean",
  									   invocationContext:"object", 
  									   onSuccess:"function", 
  									   onFailure:"function",
  									   hosts:"object",
  									   ports:"object",
  									   mqttVersion:"number"});
  			
  			// If no keep alive interval is set, assume 60 seconds.
  			if (connectOptions.keepAliveInterval === undefined)
  				connectOptions.keepAliveInterval = 60;
  
  			if (connectOptions.mqttVersion > 4 || connectOptions.mqttVersion < 3) {
  				throw new Error(format(ERROR.INVALID_ARGUMENT, [connectOptions.mqttVersion, "connectOptions.mqttVersion"]));
  			}
  
  			if (connectOptions.mqttVersion === undefined) {
  				connectOptions.mqttVersionExplicit = false;
  				connectOptions.mqttVersion = 4;
  			} else {
  				connectOptions.mqttVersionExplicit = true;
  			}
  
  			//Check that if password is set, so is username
  			if (connectOptions.password === undefined && connectOptions.userName !== undefined)
  				throw new Error(format(ERROR.INVALID_ARGUMENT, [connectOptions.password, "connectOptions.password"]))
  
  			if (connectOptions.willMessage) {
  				if (!(connectOptions.willMessage instanceof Message))
  					throw new Error(format(ERROR.INVALID_TYPE, [connectOptions.willMessage, "connectOptions.willMessage"]));
  				// The will message must have a payload that can be represented as a string.
  				// Cause the willMessage to throw an exception if this is not the case.
  				connectOptions.willMessage.stringPayload;
  				
  				if (typeof connectOptions.willMessage.destinationName === "undefined")
  					throw new Error(format(ERROR.INVALID_TYPE, [typeof connectOptions.willMessage.destinationName, "connectOptions.willMessage.destinationName"]));
  			}
  			if (typeof connectOptions.cleanSession === "undefined")
  				connectOptions.cleanSession = true;
  			if (connectOptions.hosts) {
  			    
  				if (!(connectOptions.hosts instanceof Array) )
  					throw new Error(format(ERROR.INVALID_ARGUMENT, [connectOptions.hosts, "connectOptions.hosts"]));
  				if (connectOptions.hosts.length <1 )
  					throw new Error(format(ERROR.INVALID_ARGUMENT, [connectOptions.hosts, "connectOptions.hosts"]));
  				
  				var usingURIs = false;
  				for (var i = 0; i<connectOptions.hosts.length; i++) {
  					if (typeof connectOptions.hosts[i] !== "string")
  						throw new Error(format(ERROR.INVALID_TYPE, [typeof connectOptions.hosts[i], "connectOptions.hosts["+i+"]"]));
  					if (/^(wss?):\/\/((\[(.+)\])|([^\/]+?))(:(\d+))?(\/.*)$/.test(connectOptions.hosts[i])) {
  						if (i == 0) {
  							usingURIs = true;
  						} else if (!usingURIs) {
  							throw new Error(format(ERROR.INVALID_ARGUMENT, [connectOptions.hosts[i], "connectOptions.hosts["+i+"]"]));
  						}
  					} else if (usingURIs) {
  						throw new Error(format(ERROR.INVALID_ARGUMENT, [connectOptions.hosts[i], "connectOptions.hosts["+i+"]"]));
  					}
  				}
  				
  				if (!usingURIs) {
  					if (!connectOptions.ports)
  						throw new Error(format(ERROR.INVALID_ARGUMENT, [connectOptions.ports, "connectOptions.ports"]));
  					if (!(connectOptions.ports instanceof Array) )
  						throw new Error(format(ERROR.INVALID_ARGUMENT, [connectOptions.ports, "connectOptions.ports"]));
  					if (connectOptions.hosts.length != connectOptions.ports.length)
  						throw new Error(format(ERROR.INVALID_ARGUMENT, [connectOptions.ports, "connectOptions.ports"]));
  					
  					connectOptions.uris = [];
  					
  					for (var i = 0; i<connectOptions.hosts.length; i++) {
  						if (typeof connectOptions.ports[i] !== "number" || connectOptions.ports[i] < 0)
  							throw new Error(format(ERROR.INVALID_TYPE, [typeof connectOptions.ports[i], "connectOptions.ports["+i+"]"]));
  						var host = connectOptions.hosts[i];
  						var port = connectOptions.ports[i];
  						
  						var ipv6 = (host.indexOf(":") != -1);
  						uri = "ws://"+(ipv6?"["+host+"]":host)+":"+port+path;
  						connectOptions.uris.push(uri);
  					}
  				} else {
  					connectOptions.uris = connectOptions.hosts;
  				}
  			}
  			
  			client.connect(connectOptions);
  		};
  	 
  		/** 
  		 * Subscribe for messages, request receipt of a copy of messages sent to the destinations described by the filter.
  		 * 
  		 * @name Paho.MQTT.Client#subscribe
  		 * @function
  		 * @param {string} filter describing the destinations to receive messages from.
  		 * <br>
  		 * @param {object} subscribeOptions - used to control the subscription
  		 *
  		 * @param {number} subscribeOptions.qos - the maiximum qos of any publications sent 
  		 *                                  as a result of making this subscription.
  		 * @param {object} subscribeOptions.invocationContext - passed to the onSuccess callback 
  		 *                                  or onFailure callback.
  		 * @param {function} subscribeOptions.onSuccess - called when the subscribe acknowledgement
  		 *                                  has been received from the server.
  		 *                                  A single response object parameter is passed to the onSuccess callback containing the following fields:
  		 *                                  <ol>
  		 *                                  <li>invocationContext if set in the subscribeOptions.       
  		 *                                  </ol>
  		 * @param {function} subscribeOptions.onFailure - called when the subscribe request has failed or timed out.
  		 *                                  A single response object parameter is passed to the onFailure callback containing the following fields:
  		 *                                  <ol>
  		 *                                  <li>invocationContext - if set in the subscribeOptions.       
  		 *                                  <li>errorCode - a number indicating the nature of the error.
  		 *                                  <li>errorMessage - text describing the error.      
  		 *                                  </ol>
  		 * @param {number} subscribeOptions.timeout - which, if present, determines the number of
  		 *                                  seconds after which the onFailure calback is called.
  		 *                                  The presence of a timeout does not prevent the onSuccess
  		 *                                  callback from being called when the subscribe completes.         
  		 * @throws {InvalidState} if the client is not in connected state.
  		 */
  		this.subscribe = function (filter, subscribeOptions) {
  			if (typeof filter !== "string")
  				throw new Error("Invalid argument:"+filter);
  			subscribeOptions = subscribeOptions || {} ;
  			validate(subscribeOptions,  {qos:"number", 
  										 invocationContext:"object", 
  										 onSuccess:"function", 
  										 onFailure:"function",
  										 timeout:"number"
  										});
  			if (subscribeOptions.timeout && !subscribeOptions.onFailure)
  				throw new Error("subscribeOptions.timeout specified with no onFailure callback.");
  			if (typeof subscribeOptions.qos !== "undefined" 
  				&& !(subscribeOptions.qos === 0 || subscribeOptions.qos === 1 || subscribeOptions.qos === 2 ))
  				throw new Error(format(ERROR.INVALID_ARGUMENT, [subscribeOptions.qos, "subscribeOptions.qos"]));
  			client.subscribe(filter, subscribeOptions);
  		};
  
  		/**
  		 * Unsubscribe for messages, stop receiving messages sent to destinations described by the filter.
  		 * 
  		 * @name Paho.MQTT.Client#unsubscribe
  		 * @function
  		 * @param {string} filter - describing the destinations to receive messages from.
  		 * @param {object} unsubscribeOptions - used to control the subscription
  		 * @param {object} unsubscribeOptions.invocationContext - passed to the onSuccess callback 
  		                                      or onFailure callback.
  		 * @param {function} unsubscribeOptions.onSuccess - called when the unsubscribe acknowledgement has been received from the server.
  		 *                                    A single response object parameter is passed to the 
  		 *                                    onSuccess callback containing the following fields:
  		 *                                    <ol>
  		 *                                    <li>invocationContext - if set in the unsubscribeOptions.     
  		 *                                    </ol>
  		 * @param {function} unsubscribeOptions.onFailure called when the unsubscribe request has failed or timed out.
  		 *                                    A single response object parameter is passed to the onFailure callback containing the following fields:
  		 *                                    <ol>
  		 *                                    <li>invocationContext - if set in the unsubscribeOptions.       
  		 *                                    <li>errorCode - a number indicating the nature of the error.
  		 *                                    <li>errorMessage - text describing the error.      
  		 *                                    </ol>
  		 * @param {number} unsubscribeOptions.timeout - which, if present, determines the number of seconds
  		 *                                    after which the onFailure callback is called. The presence of
  		 *                                    a timeout does not prevent the onSuccess callback from being
  		 *                                    called when the unsubscribe completes
  		 * @throws {InvalidState} if the client is not in connected state.
  		 */
  		this.unsubscribe = function (filter, unsubscribeOptions) {
  			if (typeof filter !== "string")
  				throw new Error("Invalid argument:"+filter);
  			unsubscribeOptions = unsubscribeOptions || {} ;
  			validate(unsubscribeOptions,  {invocationContext:"object", 
  										   onSuccess:"function", 
  										   onFailure:"function",
  										   timeout:"number"
  										  });
  			if (unsubscribeOptions.timeout && !unsubscribeOptions.onFailure)
  				throw new Error("unsubscribeOptions.timeout specified with no onFailure callback.");
  			client.unsubscribe(filter, unsubscribeOptions);
  		};
  
  		/**
  		 * Send a message to the consumers of the destination in the Message.
  		 * 
  		 * @name Paho.MQTT.Client#send
  		 * @function 
  		 * @param {string|Paho.MQTT.Message} topic - <b>mandatory</b> The name of the destination to which the message is to be sent. 
  		 * 					   - If it is the only parameter, used as Paho.MQTT.Message object.
  		 * @param {String|ArrayBuffer} payload - The message data to be sent. 
  		 * @param {number} qos The Quality of Service used to deliver the message.
  		 * 		<dl>
  		 * 			<dt>0 Best effort (default).
  		 *     			<dt>1 At least once.
  		 *     			<dt>2 Exactly once.     
  		 * 		</dl>
  		 * @param {Boolean} retained If true, the message is to be retained by the server and delivered 
  		 *                     to both current and future subscriptions.
  		 *                     If false the server only delivers the message to current subscribers, this is the default for new Messages. 
  		 *                     A received message has the retained boolean set to true if the message was published 
  		 *                     with the retained boolean set to true
  		 *                     and the subscrption was made after the message has been published. 
  		 * @throws {InvalidState} if the client is not connected.
  		 */   
  		this.send = function (topic,payload,qos,retained) {   
  			var message ;  
  			
  			if(arguments.length == 0){
  				throw new Error("Invalid argument."+"length");
  
  			}else if(arguments.length == 1) {
  
  				if (!(topic instanceof Message) && (typeof topic !== "string"))
  					throw new Error("Invalid argument:"+ typeof topic);
  
  				message = topic;
  				if (typeof message.destinationName === "undefined")
  					throw new Error(format(ERROR.INVALID_ARGUMENT,[message.destinationName,"Message.destinationName"]));
  				client.send(message); 
  
  			}else {
  				//parameter checking in Message object 
  				message = new Message(payload);
  				message.destinationName = topic;
  				if(arguments.length >= 3)
  					message.qos = qos;
  				if(arguments.length >= 4)
  					message.retained = retained;
  				client.send(message); 
  			}
  		};
  		
  		/** 
  		 * Normal disconnect of this Messaging client from its server.
  		 * 
  		 * @name Paho.MQTT.Client#disconnect
  		 * @function
  		 * @throws {InvalidState} if the client is already disconnected.     
  		 */
  		this.disconnect = function () {
  			client.disconnect();
  		};
  		
  		/** 
  		 * Get the contents of the trace log.
  		 * 
  		 * @name Paho.MQTT.Client#getTraceLog
  		 * @function
  		 * @return {Object[]} tracebuffer containing the time ordered trace records.
  		 */
  		this.getTraceLog = function () {
  			return client.getTraceLog();
  		}
  		
  		/** 
  		 * Start tracing.
  		 * 
  		 * @name Paho.MQTT.Client#startTrace
  		 * @function
  		 */
  		this.startTrace = function () {
  			client.startTrace();
  		};
  		
  		/** 
  		 * Stop tracing.
  		 * 
  		 * @name Paho.MQTT.Client#stopTrace
  		 * @function
  		 */
  		this.stopTrace = function () {
  			client.stopTrace();
  		};
  
  		this.isConnected = function() {
  			return client.connected;
  		};
  	};
  
  	Client.prototype = {
  		get host() { return this._getHost(); },
  		set host(newHost) { this._setHost(newHost); },
  			
  		get port() { return this._getPort(); },
  		set port(newPort) { this._setPort(newPort); },
  
  		get path() { return this._getPath(); },
  		set path(newPath) { this._setPath(newPath); },
  			
  		get clientId() { return this._getClientId(); },
  		set clientId(newClientId) { this._setClientId(newClientId); },
  
  		get onConnectionLost() { return this._getOnConnectionLost(); },
  		set onConnectionLost(newOnConnectionLost) { this._setOnConnectionLost(newOnConnectionLost); },
  
  		get onMessageDelivered() { return this._getOnMessageDelivered(); },
  		set onMessageDelivered(newOnMessageDelivered) { this._setOnMessageDelivered(newOnMessageDelivered); },
  		
  		get onMessageArrived() { return this._getOnMessageArrived(); },
  		set onMessageArrived(newOnMessageArrived) { this._setOnMessageArrived(newOnMessageArrived); },
  
  		get trace() { return this._getTrace(); },
  		set trace(newTraceFunction) { this._setTrace(newTraceFunction); }	
  
  	};
  	
  	/** 
  	 * An application message, sent or received.
  	 * <p>
  	 * All attributes may be null, which implies the default values.
  	 * 
  	 * @name Paho.MQTT.Message
  	 * @constructor
  	 * @param {String|ArrayBuffer} payload The message data to be sent.
  	 * <p>
  	 * @property {string} payloadString <i>read only</i> The payload as a string if the payload consists of valid UTF-8 characters.
  	 * @property {ArrayBuffer} payloadBytes <i>read only</i> The payload as an ArrayBuffer.
  	 * <p>
  	 * @property {string} destinationName <b>mandatory</b> The name of the destination to which the message is to be sent
  	 *                    (for messages about to be sent) or the name of the destination from which the message has been received.
  	 *                    (for messages received by the onMessage function).
  	 * <p>
  	 * @property {number} qos The Quality of Service used to deliver the message.
  	 * <dl>
  	 *     <dt>0 Best effort (default).
  	 *     <dt>1 At least once.
  	 *     <dt>2 Exactly once.     
  	 * </dl>
  	 * <p>
  	 * @property {Boolean} retained If true, the message is to be retained by the server and delivered 
  	 *                     to both current and future subscriptions.
  	 *                     If false the server only delivers the message to current subscribers, this is the default for new Messages. 
  	 *                     A received message has the retained boolean set to true if the message was published 
  	 *                     with the retained boolean set to true
  	 *                     and the subscrption was made after the message has been published. 
  	 * <p>
  	 * @property {Boolean} duplicate <i>read only</i> If true, this message might be a duplicate of one which has already been received. 
  	 *                     This is only set on messages received from the server.
  	 *                     
  	 */
  	var Message = function (newPayload) {  
  		var payload;
  		if (   typeof newPayload === "string" 
  			|| newPayload instanceof ArrayBuffer
  			|| newPayload instanceof Int8Array
  			|| newPayload instanceof Uint8Array
  			|| newPayload instanceof Int16Array
  			|| newPayload instanceof Uint16Array
  			|| newPayload instanceof Int32Array
  			|| newPayload instanceof Uint32Array
  			|| newPayload instanceof Float32Array
  			|| newPayload instanceof Float64Array
  		   ) {
  			payload = newPayload;
  		} else {
  			throw (format(ERROR.INVALID_ARGUMENT, [newPayload, "newPayload"]));
  		}
  
  		this._getPayloadString = function () {
  			if (typeof payload === "string")
  				return payload;
  			else
  				return parseUTF8(payload, 0, payload.length); 
  		};
  
  		this._getPayloadBytes = function() {
  			if (typeof payload === "string") {
  				var buffer = new ArrayBuffer(UTF8Length(payload));
  				var byteStream = new Uint8Array(buffer); 
  				stringToUTF8(payload, byteStream, 0);
  
  				return byteStream;
  			} else {
  				return payload;
  			};
  		};
  
  		var destinationName = undefined;
  		this._getDestinationName = function() { return destinationName; };
  		this._setDestinationName = function(newDestinationName) { 
  			if (typeof newDestinationName === "string")
  				destinationName = newDestinationName;
  			else 
  				throw new Error(format(ERROR.INVALID_ARGUMENT, [newDestinationName, "newDestinationName"]));
  		};
  				
  		var qos = 0;
  		this._getQos = function() { return qos; };
  		this._setQos = function(newQos) { 
  			if (newQos === 0 || newQos === 1 || newQos === 2 )
  				qos = newQos;
  			else 
  				throw new Error("Invalid argument:"+newQos);
  		};
  
  		var retained = false;
  		this._getRetained = function() { return retained; };
  		this._setRetained = function(newRetained) { 
  			if (typeof newRetained === "boolean")
  				retained = newRetained;
  			else 
  				throw new Error(format(ERROR.INVALID_ARGUMENT, [newRetained, "newRetained"]));
  		};
  		
  		var duplicate = false;
  		this._getDuplicate = function() { return duplicate; };
  		this._setDuplicate = function(newDuplicate) { duplicate = newDuplicate; };
  	};
  	
  	Message.prototype = {
  		get payloadString() { return this._getPayloadString(); },
  		get payloadBytes() { return this._getPayloadBytes(); },
  		
  		get destinationName() { return this._getDestinationName(); },
  		set destinationName(newDestinationName) { this._setDestinationName(newDestinationName); },
  		
  		get qos() { return this._getQos(); },
  		set qos(newQos) { this._setQos(newQos); },
  
  		get retained() { return this._getRetained(); },
  		set retained(newRetained) { this._setRetained(newRetained); },
  
  		get duplicate() { return this._getDuplicate(); },
  		set duplicate(newDuplicate) { this._setDuplicate(newDuplicate); }
  	};
  	   
  	// Module contents.
  	return {
  		Client: Client,
  		Message: Message
  	};
  })(window);
  
  export default {
  	MQTT:　Paho.MQTT
  }