- improved 'percent-decoded-p'.

src/text-utils.lisp

@@ -677,10 +677,23 @@ printed in the box column by column; in the example above the results are:
 (defun percent-decode (string)
   (percent-encoding:decode string :encoding :utf-8))
 
+(defun percent-decode-allow-null (data)
+  (when data
+    (percent-decode data)))
+
 (defun percent-encoded-p (string)
-  (conditions:with-default-on-error (t)
-    (string/= string
-              (percent-decode string))))
+  (loop for i in (coerce string 'list)
+        for ct from 0 do
+          (cond
+            ((char= i #\%)
+             (when (not (cl-ppcre:scan "(?i)^%[0123456789abcdef]{2}" string :start ct))
+               (return-from percent-encoded-p nil)))
+            ((or (percent:reservedp i)
+                 (char= i #\Space)
+                 (not (or (percent:alphap (char-code i))
+                          (percent:digitp (char-code i)))))
+             (return-from percent-encoded-p nil))))
+  t)
 
 (defun percent-encode-allow-null (data)
   (when data