From 3270e03da1097f8054e12c1d1e5fa5408a91be7b Mon Sep 17 00:00:00 2001
From: Henning Guenther <h.guenther@tu-bs.de>
Date: Thu, 26 Feb 2009 06:46:53 -0800
Subject: [PATCH] Made decoding array lookup safe

Ignore-this: 346535974ae363daf4ade7e22ed48ad7

darcs-hash:20090226144653-a4fee-42808f15a3bab3fa1712ab12d8b0cfb54ff96aad
---
 Data/Encoding/Base.hs | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/Data/Encoding/Base.hs b/Data/Encoding/Base.hs
index f4318aa..8b03007 100644
--- a/Data/Encoding/Base.hs
+++ b/Data/Encoding/Base.hs
@@ -76,7 +76,11 @@ decodeWithArray2 :: ByteSource m => UArray (Word8,Word8) Int -> m Char
 decodeWithArray2 arr = do
   w1 <- fetchWord8
   w2 <- fetchWord8
-  let res = arr!(w1,w2)
-  if res < 0
-    then throwException $ IllegalCharacter w1
-    else return $ chr res
\ No newline at end of file
+  if inRange (bounds arr) (w1,w2)
+    then (do
+           let res = arr!(w1,w2)
+           if res < 0
+             then throwException $ IllegalCharacter w1
+             else return $ chr res
+         )
+    else throwException $ IllegalCharacter w1
\ No newline at end of file