fix writing empty string to buffer. closes briancgh-39

Author: brianc

lib/writer.js

@@ -37,7 +37,12 @@ p.addInt16 = function(num) {
 }
 
 p.addCString = function(string) {
-  var string = string || "";
+  //just write a 0 for empty or null strings
+  if(!string) {
+    this._ensure(1);
+    this.buffer[this.offset++] = 0;
+    return this;
+  }
   var len = Buffer.byteLength(string) + 1;
   this._ensure(len);
   this.buffer.write(string, this.offset);

test/unit/writer-tests.js

@@ -66,6 +66,13 @@ test('cString', function() {
     var result = subject.addCString().join();
     assert.equalBuffers(result, [0])
   })
+  
+  test('writes two empty cstrings', function() {
+    var subject = new Writer();
+    var result = subject.addCString("").addCString("").join();
+    assert.equalBuffers(result, [0, 0])
+  })
+
 
   test('writes non-empty cstring', function() {
     var subject = new Writer();