some cleanup and comments

lib/parser/javascript.js

@@ -27,42 +27,46 @@ exports.Parser = FasterReplyParser;
 FasterReplyParser.prototype._parseResult = function (type) {
     var start, end, offset, packetHeader;
   
-    if (type === 43 || type === 45) { // +
+    if (type === 43 || type === 45) { // + or -
+        // up to the delimiter
         end = this._packetEndOffset() - 1;
         start = this._offset;
 
+        // include the delimiter
         this._offset = end + 2;
 
         if (this.options.return_buffers) {
             return this._buffer.slice(start, end);
         } else {
-            return this._buffer.slice(start, end).toString(this._encoding);
+            return this._buffer.toString(this._encoding, start, end);
         }
     } else if (type === 58) { // :
+        // up to the delimiter
         end = this._packetEndOffset() - 1;
         start = this._offset;
 
+        // include the delimiter
         this._offset = end + 2;
 
+        // return the coerced numeric value
         return +this._buffer.toString(this._encoding, start, end);
     } else if (type === 36) { // $
+        // set a rewind point, as the packet could be larger than the
+        // buffer in memory
         offset = this._offset - 1;
 
         packetHeader = new Packet(type, this.parseHeader());
 
-        if (packetHeader.size === null) {
-            this._offset++;
-
-            return null;
-        }
-
+        // packets with a size of -1 are considered null
         if (packetHeader.size === -1) {
             return null;
         }
 
+
         end = this._offset + packetHeader.size;
         start = this._offset;
 
+        // set the offset to after the delimiter
         this._offset = end + 2;
 
         if (end > this._buffer.length) {
@@ -73,7 +77,7 @@ FasterReplyParser.prototype._parseResult = function (type) {
         if (this.options.return_buffers) {
             return this._buffer.slice(start, end);
         } else {
-            return this._buffer.slice(start, end).toString(this._encoding);
+            return this._buffer.toString(this._encoding, start, end);
         }
     } else if (type === 42) { // *
         offset = this._offset;
@@ -113,7 +117,7 @@ FasterReplyParser.prototype.execute = function (buffer) {
         try {
             var ret;
       
-            // at least 4 bytes: *1\r\n
+            // at least 4 bytes: :1\r\n
             if (this._bytesRemaining() < 4) {
                 break;
             }
@@ -123,7 +127,7 @@ FasterReplyParser.prototype.execute = function (buffer) {
             if (type === 43) { // +
                 ret = this._parseResult(type);
                 this.send_reply(ret);
-            } else  if (type === 45) {
+            } else  if (type === 45) { // -
                 ret = this._parseResult(type);
                 this.send_error(ret);
             } else if (type === 58) { // :
@@ -132,11 +136,10 @@ FasterReplyParser.prototype.execute = function (buffer) {
             } else if (type === 36) { // $
                 ret = this._parseResult(type);
 
-                if (ret === null) {
-                    break;
-                }
                 this.send_reply(ret);
             } else if (type === 42) { // *
+                // set a rewind point. if a failure occurs,
+                // wait for the next execute()/append() and try again
                 offset = this._offset - 1;
                 ret = this._parseResult(type);
                 if (ret === -1) {
@@ -147,6 +150,8 @@ FasterReplyParser.prototype.execute = function (buffer) {
                 this.send_reply(ret);
             }
         } catch(err) {
+            // catch the error (not enough data), rewind, and wait
+            // for the next packet to appear
             this._offset = offset;
             break;
         }
@@ -158,26 +163,23 @@ FasterReplyParser.prototype.append = function(newBuffer) {
         return;
     }
 
-    var oldBuffer = this._buffer;
-    if (!oldBuffer) {
+    // first run
+    if (this._buffer === null) {
         this._buffer = newBuffer;
 
         return;
     }
 
-    var bytesRemaining = this._bytesRemaining();
-  
-    var newLength = bytesRemaining + newBuffer.length;
-
-    if (bytesRemaining === 0) {
+    // out of data
+    if (this._offset >= this._buffer.length) {
         this._buffer = newBuffer;
         this._offset = 0;
 
         return;
     }
 
+    // very large packet
     this._buffer = Buffer.concat([this._buffer.slice(this._offset), newBuffer]);
-
     this._offset = 0;
 };
 
@@ -190,13 +192,6 @@ FasterReplyParser.prototype.parseHeader = function () {
     return value;
 };
 
-FasterReplyParser.prototype.parseBuffer = function(length) {
-    var buffer = this._buffer.slice(this._offset, this._offset + length);
-
-    this._offset += length;
-    return buffer;
-};
-
 FasterReplyParser.prototype._packetEndOffset = function () {
     var offset = this._offset;