improved performance by concating buffers as a late as possible

Author: themasch

lib/encode.js

@@ -7,77 +7,79 @@
  */
 function encode( data ) {
 
+  var buffers = []
+  encode._encode( buffers, data)
+  return Buffer.concat(buffers)
+}
+
+encode._encode = function( buffers, data ) {
+
   if( data instanceof Buffer ) {
-    return Buffer.concat([
-      new Buffer(data.length+':'),
-      data
-    ])
+    buffers.push(new Buffer(data.length+':'))
+    buffers.push(data)
+    return;
   }
 
   switch( typeof data ) {
     case 'string':
-      return encode.bytes( data )
+      encode.bytes( buffers, data )
       break
     case 'number':
-      return encode.number( data )
+      encode.number( buffers, data )
       break
     case 'object':
-      return data.constructor === Array
-        ? encode.list( data )
-        : encode.dict( data )
+      data.constructor === Array
+        ? encode.list( buffers, data )
+        : encode.dict( buffers, data )
       break
   }
-
 }
 
 var buff_e = new Buffer('e')
   , buff_d = new Buffer('d')
   , buff_l = new Buffer('l')
 
-encode.bytes = function( data ) {
-  return Buffer.concat([
-    new Buffer(Buffer.byteLength( data )+":"),
-    new Buffer(data)
-  ])
+encode.bytes = function( buffers, data ) {
+
+  buffers.push( new Buffer(Buffer.byteLength( data )+":") )
+  buffers.push( new Buffer(data) )
 }
 
-encode.number = function( data ) {
-  return new Buffer('i' + data + 'e')
+encode.number = function( buffers, data ) {
+
+  buffers.push( new Buffer('i' + data + 'e') )
 }
 
-encode.dict = function( data ) {
+encode.dict = function( buffers, data ) {
+
+  buffers.push( buff_d )
+
+  var j = 0
 
-  var dict = [ buff_d ]
-  var i = 1;
   // fix for issue #13 - sorted dicts
-  var keys = []
-  for( var k in data) {
-    keys.push(k)
-  }
-  keys = keys.sort()
+  var keys = Object.keys(data).sort()
+  var kl = keys.length
 
-  for(var j=0;j<keys.length;j++) {
-    dict[i++] = encode( keys[j] )
-    dict[i++] = encode( data[keys[j]] )
+  for( ; j < kl ; j++ ) {
+    encode.bytes( buffers, keys[j] )
+    encode._encode( buffers, data[keys[j]] )
   }
 
-  dict[i++] = buff_e
-  return Buffer.concat(dict)
+  buffers.push( buff_e )
 
 }
 
-encode.list = function( data ) {
+encode.list = function( buffers, data ) {
 
   var i = 0, j = 1
   var c = data.length
-  var lst =  [ buff_l ]
+  buffers.push( buff_l )
 
   for( ; i < c; i++ ) {
-    lst[j++] = encode( data[i] )
+    encode._encode( buffers, data[i] )
   }
 
-  lst[j++] = buff_e
-  return Buffer.concat(lst)
+  buffers.push( buff_e )
 
 }