Make decode case insensitive.

> 6.  Base 32 Encoding
>
>   The Base 32 encoding is designed to represent arbitrary sequences of
> octets in a form that _needs to be case insensitive_ but that need not
> be human readable.

2 files changed, 13 insertions, 7 deletions

diff --git a/src/Data/ByteString/Base32.hs b/src/Data/ByteString/Base32.hs
index 5dc025c..a5835ad 100644
--- a/src/Data/ByteString/Base32.hs
+++ b/src/Data/ByteString/Base32.hs
@@ -227,11 +227,13 @@ pack5 !tbl bs @ (PS fptr off sz) =
 
 decW5 :: Word8 -> Word5
 decW5 !x
-  | x <  50 {- c2w '2' -} = invIx
-  | x <= 55 {- c2w '7' -} = x - 24
-  | x <  65 {- c2w 'A' -} = invIx
-  | x <= 90 {- c2w 'Z' -} = x - 65
-  |       otherwise       = invIx
+  | x <  50  {- c2w '2' -} = invIx
+  | x <= 55  {- c2w '7' -} = x - 24 {- c2w '2' - 26 -}
+  | x <  65  {- c2w 'A' -} = invIx
+  | x <= 90  {- c2w 'Z' -} = x - 65 {- c2w 'A' -}
+  | x <  97  {- c2w 'a' -} = invIx
+  | x <= 122 {- c2w 'z' -} = x - 97 {- c2w 'a' -}
+  | otherwise = invIx
 {-# INLINE decW5 #-}
 
 decTable :: ForeignPtr Word8
diff --git a/tests/Data/ByteString/Base32Spec.hs b/tests/Data/ByteString/Base32Spec.hs
index ff3e13c..60e340c 100644
--- a/tests/Data/ByteString/Base32Spec.hs
+++ b/tests/Data/ByteString/Base32Spec.hs
@@ -4,8 +4,9 @@ module Data.ByteString.Base32Spec (spec) where
 import Control.Applicative
 import Control.Exception
 import Data.ByteString as BS
-import Data.ByteString.Internal as BS
+import Data.ByteString.Char8 as BC
 import Data.ByteString.Base32 as Base32
+import Data.Char
 import Test.Hspec
 import Test.QuickCheck
 
@@ -29,7 +30,7 @@ spec = do
       (BS.length (encode bs) `rem` 8) `shouldBe` 0
 
     it "padding less than" $ property $ \bs ->
-      count (c2w '=') bs `shouldSatisfy` (< 8)
+      BC.count '=' bs `shouldSatisfy` (< 8)
 
   describe "decode" $ do
     it "conform RFC examples" $ do
@@ -44,6 +45,9 @@ spec = do
     it "inverse for encode" $ property $ \bs ->
       decode (encode bs) == bs
 
+    it "case insensitive" $ property $ \bs ->
+      decode (BC.map toLower (encode bs)) == bs
+
     it "fail gracefully if encoded data contains non alphabet chars" $ do
       evaluate (decode "0=======")         `shouldThrow` anyErrorCall
       evaluate (decode "AAAAAAAA0=======") `shouldThrow` anyErrorCall