Merge pull request #21 from uken/perf-improvements

improve performance of WebSocket for large messages

Author: Animesh Kumar

.gitignore

@@ -0,0 +1,3 @@
+.project
+bin
+gen

assets/www/js/websocket.js

@@ -1,7 +1,7 @@
 /*
  * Copyright (c) 2010 Animesh Kumar  (https://github.com/anismiles)
  * Copyright (c) 2010 Strumsoft  (https://strumsoft.com)
- *  
+ *
  * Permission is hereby granted, free of charge, to any person
  * obtaining a copy of this software and associated documentation
  * files (the "Software"), to deal in the Software without
@@ -10,10 +10,10 @@
  * copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following
  * conditions:
- *  
+ *
  * The above copyright notice and this permission notice shall be
  * included in all copies or substantial portions of the Software.
- *  
+ *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
@@ -22,13 +22,13 @@
  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  * OTHER DEALINGS IN THE SOFTWARE.
- *  
+ *
  */
 (function() {
-	
+
 	// window object
 	var global = window;
-	
+
 	// WebSocket Object. All listener methods are cleaned up!
 	var WebSocket = global.WebSocket = function(url) {
 		// get a new websocket object from factory (check com.strumsoft.websocket.WebSocketFactory.java)
@@ -40,23 +40,94 @@
 			throw new Error('Websocket instantiation failed! Address might be wrong.');
 		}
 	};
-	
+
+	// private property
+	WebSocket._keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
+
+	// private method for decoding base64
+	WebSocket._decode = function (input) {
+		var output = "";
+		var chr1, chr2, chr3;
+		var enc1, enc2, enc3, enc4;
+		var i = 0;
+
+		input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
+
+		while (i < input.length) {
+
+			enc1 = this._keyStr.indexOf(input.charAt(i++));
+			enc2 = this._keyStr.indexOf(input.charAt(i++));
+			enc3 = this._keyStr.indexOf(input.charAt(i++));
+			enc4 = this._keyStr.indexOf(input.charAt(i++));
+
+			chr1 = (enc1 << 2) | (enc2 >> 4);
+			chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
+			chr3 = ((enc3 & 3) << 6) | enc4;
+
+			output = output + String.fromCharCode(chr1);
+
+			if (enc3 != 64) {
+				output = output + String.fromCharCode(chr2);
+			}
+			if (enc4 != 64) {
+				output = output + String.fromCharCode(chr3);
+			}
+
+		}
+
+		output = this._utf8_decode(output);
+
+		return output;
+
+	}
+
+	// private method for UTF-8 decoding
+	WebSocket._utf8_decode = function (utftext) {
+		var string = "";
+		var i = 0;
+		var c = c1 = c2 = 0;
+
+		while ( i < utftext.length ) {
+
+			c = utftext.charCodeAt(i);
+
+			if (c < 128) {
+				string += String.fromCharCode(c);
+				i++;
+			}
+			else if((c > 191) && (c < 224)) {
+				c2 = utftext.charCodeAt(i+1);
+				string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
+				i += 2;
+			}
+			else {
+				c2 = utftext.charCodeAt(i+1);
+				c3 = utftext.charCodeAt(i+2);
+				string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
+				i += 3;
+			}
+
+		}
+
+		return string;
+	}
+
 	// storage to hold websocket object for later invokation of event methods
 	WebSocket.store = {};
-	
+
 	// static event methods to call event methods on target websocket objects
 	WebSocket.onmessage = function (evt) {
-		WebSocket.store[evt._target]['onmessage'].call(global, evt);
-	}	
-	
+		WebSocket.store[evt._target]['onmessage'].call(global, this._decode(evt._data));
+	}
+
 	WebSocket.onopen = function (evt) {
 		WebSocket.store[evt._target]['onopen'].call(global, evt);
 	}
-	
+
 	WebSocket.onclose = function (evt) {
 		WebSocket.store[evt._target]['onclose'].call(global, evt);
 	}
-	
+
 	WebSocket.onerror = function (evt) {
 		WebSocket.store[evt._target]['onerror'].call(global, evt);
 	}
@@ -69,27 +140,27 @@
 	WebSocket.prototype.close = function() {
 		this.socket.close();
 	}
-	
+
 	WebSocket.prototype.getReadyState = function() {
 		this.socket.getReadyState();
 	}
 	///////////// Must be overloaded
 	WebSocket.prototype.onopen = function(){
 		throw new Error('onopen not implemented.');
     };
-    
+
     // alerts message pushed from server
     WebSocket.prototype.onmessage = function(msg){
     	throw new Error('onmessage not implemented.');
     };
-    
+
     // alerts message pushed from server
     WebSocket.prototype.onerror = function(msg){
     	throw new Error('onerror not implemented.');
     };
-    
+
     // alert close event
     WebSocket.prototype.onclose = function(){
         throw new Error('onclose not implemented.');
     };
-})();
+})();