hmac: use buf-xor-pattern function.

* stdlib/hmac.tl (hmac-impl): Eliminate xor loop
by using buf-xor-pattern.

1 files changed, 9 insertions, 11 deletions

diff --git a/stdlib/hmac.tl b/stdlib/hmac.tl
index fc487cbe..5b4aeb7f 100644
--- a/stdlib/hmac.tl
+++ b/stdlib/hmac.tl
@@ -39,17 +39,15 @@
 
   (buf-set-length key block-size)
 
-  (for ((i 0) (okey (copy-buf key)) (ikey (copy-buf key))
-        (ctx0 [begin-fn]) (ctx1 [begin-fn]))
-       ((< i block-size)
-        [update-fn ctx0 ikey]
-        [update-fn ctx0 message]
-        [update-fn ctx1 okey]
-        [update-fn ctx1 [end-fn ctx0]]
-        [end-fn ctx1])
-       ((inc i))
-    (upd [okey i] (logxor #x5c))
-    (upd [ikey i] (logxor #x36))))
+  (let ((okey (buf-xor-pattern key #x5c))
+        (ikey (buf-xor-pattern key #x36))
+        (ctx0 [begin-fn])
+        (ctx1 [begin-fn]))
+    [update-fn ctx0 ikey]
+    [update-fn ctx0 message]
+    [update-fn ctx1 okey]
+    [update-fn ctx1 [end-fn ctx0]]
+    [end-fn ctx1]))
 
 (defun hmac-sha1 (key message)
   [hmac-impl key message sha1 sha1-begin sha1-hash sha1-end 64])