Apply @zingaburga's StreamReader optimisations from https://github.com/faye/websocket-driver-node/issues/10.

lib/websocket/driver/hybi/stream_reader.js

@@ -3,7 +3,6 @@
 var StreamReader = function() {
   this._queue     = [];
   this._queueSize = 0;
-  this._cursor    = 0;
 };
 
 StreamReader.prototype.put = function(buffer) {
@@ -15,29 +14,49 @@ StreamReader.prototype.put = function(buffer) {
 
 StreamReader.prototype.read = function(length) {
   if (length > this._queueSize) return null;
+  if (length === 0) return new Buffer(0);
+  
+  var queue = this._queue,
+      first = queue[0],
+      buffer;
+  
+  if (first.length >= length) {
+    this._queueSize -= length;
+    if (first.length === length) {
+      return queue.shift();
+    } else {
+      buffer = first.slice(0, length);
+      queue[0] = first.slice(length);
+      return buffer;
+    }
+  }
+  
+  var remain = length, buffers;
+
+  for (var i=0, n = queue.length; i < n; i++) {
+    if (remain < queue[i].length) break;
+    remain -= queue[i].length;
+  }
+  buffers = queue.splice(0, i);
+
+  if (remain > 0 && queue.length > 0) {
+    buffers.push(queue[0].slice(0, remain));
+    queue[0] = queue[0].slice(remain);
+  }
+  this._queueSize -= length;
+  return this._concat(buffers, length);
+};
+
+StreamReader.prototype._concat = function(buffers, length) {
+  if (Buffer.concat) return Buffer.concat(buffers, length);
 
   var buffer = new Buffer(length),
-      queue  = this._queue,
-      remain = length,
-      n      = queue.length,
-      i      = 0,
-      chunk, size;
+      offset = 0;
 
-  while (remain > 0 && i < n) {
-    chunk = queue[i];
-    size  = Math.min(remain, chunk.length - this._cursor);
-
-    chunk.copy(buffer, length - remain, this._cursor, this._cursor + size);
-
-    remain          -= size;
-    this._queueSize -= size;
-    this._cursor     = (this._cursor + size) % chunk.length;
-
-    i += 1;
+  for (var i = 0, n = buffers.length; i < n; i++) {
+    buffers[i].copy(buffer, offset);
+    offset += buffers[i].length;
   }
-
-  queue.splice(0, this._cursor === 0 ? i : i - 1);
-
   return buffer;
 };