Add script that checks the encoding of all the files

The script check_encoding.py raises an expection if it finds a file
that is not encoded with UTF8.

diff --git a/contrib/utilities/check_encoding.py b/contrib/utilities/check_encoding.py
new file mode 100755 (executable)
index 0000000..bad19a3
--- /dev/null
+++ b/contrib/utilities/check_encoding.py
@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+## ---------------------------------------------------------------------
+##
+## Copyright (C) 2019 by the deal.II authors
+##
+## This file is part of the deal.II library.
+##
+## The deal.II library is free software; you can use it, redistribute
+## it, and/or modify it under the terms of the GNU Lesser General
+## Public License as published by the Free Software Foundation; either
+## version 2.1 of the License, or (at your option) any later version.
+## The full text of the license can be found in the file LICENSE at
+## the top level of the deal.II distribution.
+##
+## ---------------------------------------------------------------------
+
+# This script checks if the files in the deal.II repository are encoded with
+# valid UTF8.
+#
+# This script should be invoked from the root folder of the deal.ii
+# repository:
+# contrib/utilities/check_encoding.py
+
+import glob
+import itertools
+
+filenames = itertools.chain(glob.iglob('**/*.h', recursive=True),
+                            glob.iglob('**/*.cc', recursive=True),
+                            glob.iglob('**/*.html', recursive=True))
+
+for filename in filenames:
+    try:
+        with open(filename, encoding='utf-8') as file:
+            file.read()
+    except:
+        raise Exception(filename + ' is not encoded is not encoded with UTF-8')