diff --git a/tamper/charunicodeescape.py b/tamper/charunicodeescape.py
index 8fc8c7aca..a9fb0b473 100644
--- a/tamper/charunicodeescape.py
+++ b/tamper/charunicodeescape.py
@@ -30,9 +30,9 @@ def tamper(payload, **kwargs):
     if payload:
         retVal = ""
         i = 0
-
-        while i < len(payload):
-            if payload[i] == '%' and (i < len(payload) - 2) and payload[i + 1:i + 2] in string.hexdigits and payload[i + 2:i + 3] in string.hexdigits:
+        payloadLength = len(payload)
+        while i < payloadLength:
+            if payload[i] == '%' and (i < payloadLength - 2) and payload[i + 1:i + 2] in string.hexdigits and payload[i + 2:i + 3] in string.hexdigits:
                 retVal += "\\u00%s" % payload[i + 1:i + 3]
                 i += 3
             else: