Give forward plugin its own folder. Should make it easier to clean it up.

lib/units/device/plugins/forward/util/reader.js

@@ -0,0 +1,75 @@
+var util = require('util')
+var stream = require('stream')
+
+var HEADER_SIZE = 4
+
+function ForwardReader() {
+  stream.Transform.call(this)
+  this._header = new Buffer(HEADER_SIZE)
+  this._needLength = -HEADER_SIZE
+  this._target = 0
+}
+
+util.inherits(ForwardReader, stream.Transform)
+
+ForwardReader.prototype._transform = function(chunk, encoding, done) {
+  var cursor = 0
+
+  while (cursor < chunk.length) {
+    var diff = chunk.length - cursor
+
+    // Do we need a header?
+    if (this._needLength < 0) {
+      // Still missing a header?
+      if (chunk.length < -this._needLength) {
+        // Save what we're received so far.
+        chunk.copy(
+          this._header
+        , HEADER_SIZE + this._needLength
+        , cursor
+        , cursor + -this._needLength
+        )
+        break
+      }
+
+      // Combine previous and current chunk in case the header was split.
+      chunk.copy(
+        this._header
+      , HEADER_SIZE + this._needLength
+      , cursor
+      , cursor + -this._needLength
+      )
+
+      cursor += -this._needLength
+
+      this._target = this._header.readUInt16LE(0)
+      this._needLength = this._header.readUInt16LE(2)
+
+      if (this._needLength === 0) {
+        // This is a fin packet
+        this.emit('packet', this._target, null)
+        this._needLength = -HEADER_SIZE
+      }
+    }
+    // Do we have a full data packet?
+    else if (diff >= this._needLength) {
+      this.emit(
+        'packet'
+      , this._target
+      , chunk.slice(cursor, cursor + this._needLength)
+      )
+      cursor += this._needLength
+      this._needLength = -HEADER_SIZE
+    }
+    // We have a partial data packet.
+    else {
+      this.emit('packet', this._target, chunk.slice(cursor, cursor + diff))
+      this._needLength -= diff
+      cursor += diff
+    }
+  }
+
+  done()
+}
+
+module.exports = ForwardReader