diff --git a/generate-encoding-data.py b/generate-encoding-data.py
index ddcefd6..ce0d286 100644
--- a/generate-encoding-data.py
+++ b/generate-encoding-data.py
@@ -109,18 +109,29 @@ def is_single_byte(name):
       return True
   return False
 
-label_file = open("src/labels.rs", "w")
+label_file = open("src/lib.rs", "r")
+lib_rs_full = label_file.read()
+label_file.close()
 
-label_file.write("""// Copyright 2015-2016 Mozilla Foundation. See the COPYRIGHT
-// file at the top-level directory of this distribution.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
+generated_begin = "// BEGIN GENERATED CODE. PLEASE DO NOT EDIT."
+generated_end = "// END GENERATED CODE"
 
-// BEGIN GENERATED CODE. PLEASE DO NOT EDIT.
+generated_begin_index = lib_rs_full.find(generated_begin)
+if generated_begin_index < 0:
+  print "Can't find generated code start marker in lib.rs. Exiting."
+  sys.exit(-1)
+generated_end_index = lib_rs_full.find(generated_end)
+if generated_end_index < 0:
+  print "Can't find generated code end marker in lib.rs. Exiting."
+  sys.exit(-1)
+
+lib_rs_begin = lib_rs_full[0:generated_begin_index + len(generated_begin)]
+lib_rs_end = lib_rs_full[generated_end_index:]
+
+label_file = open("src/lib.rs", "w")
+
+label_file.write(lib_rs_begin)
+label_file.write("""
 // Instead, please regenerate using generate-encoding-data.py
 
 const LONGEST_LABEL_LENGTH: usize = %d; // %s
@@ -167,9 +178,8 @@ for label in labels:
   
 label_file.write('''];
 
-// END GENERATED CODE
 ''')
-
+label_file.write(lib_rs_end)
 label_file.close()
 
 def null_to_zero(code_point):