Make ASCII-lowercasing quicker when it's a no-op

gsnedders · gsnedders · commit 42f95ed86eca · 2016-06-07T17:36:18.000+01:00
diff --git a/html5lib/utils.py b/html5lib/utils.py
@@ -1,6 +1,8 @@
 from __future__ import absolute_import, division, unicode_literals
 
+import re
 import sys
+
 from types import ModuleType
 
 from six import text_type
@@ -128,5 +130,11 @@ def wrapped(*args, **kwargs):
     return wrapped
 
 
+_upper = re.compile(u"[A-Z]")
+
+
 def ascii_lowercase(s):
-    return s.translate(asciiUpper2Lower)
+    if _upper.search(s) is not None:
+        return s.translate(asciiUpper2Lower)
+    else:
+        return s
