From d6f2f7c1c0c809952cbcb3cfb4602059d347a447 Mon Sep 17 00:00:00 2001
From: Vincent Hanquez <vincent@snarc.org>
Date: Sun, 12 Apr 2015 06:50:54 +0100
Subject: [PATCH] [Cipher] make xtsGFMul work on arbitrary ByteArray

---
 Crypto/Cipher/Types/GF.hs | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/Crypto/Cipher/Types/GF.hs b/Crypto/Cipher/Types/GF.hs
index 647a973..2fa48e2 100644
--- a/Crypto/Cipher/Types/GF.hs
+++ b/Crypto/Cipher/Types/GF.hs
@@ -14,10 +14,7 @@ module Crypto.Cipher.Types.GF
     ) where
 
 import Control.Applicative
-import Data.ByteString (ByteString)
-import qualified Data.ByteString as B
-import qualified Data.ByteString.Internal as B
-import Data.Byteable
+import Crypto.Internal.ByteArray
 import Foreign.Storable
 import Foreign.Ptr
 import Data.Word
@@ -26,14 +23,15 @@ import Data.Bits
 -- block size need to be 128 bits.
 --
 -- FIXME: add support for big endian.
-xtsGFMul :: ByteString -> ByteString
+xtsGFMul :: ByteArray ba => ba -> ba
 xtsGFMul b
-    | B.length b == 16 = B.unsafeCreate (B.length b) $ \dst ->
-                         withBytePtr b $ \src -> do
-                         (hi,lo) <- gf <$> peek (castPtr src) <*> peek (castPtr src `plusPtr` 8)
-                         poke (castPtr dst) lo
-                         poke (castPtr dst `plusPtr` 8) hi
-    | otherwise        = error "unsupported block size in GF"
+    | len == 16 =
+        byteArrayAllocAndFreeze len $ \dst ->
+        withByteArray b             $ \src -> do
+            (hi,lo) <- gf <$> peek (castPtr src) <*> peek (castPtr src `plusPtr` 8)
+            poke (castPtr dst) lo
+            poke (castPtr dst `plusPtr` 8) hi
+    | otherwise = error "unsupported block size in GF"
   where gf :: Word64 -> Word64 -> (Word64, Word64)
         gf srcLo srcHi =
             ((if carryLo then (.|. 1) else id) (srcHi `shiftL` 1)
@@ -41,6 +39,7 @@ xtsGFMul b
             )
           where carryHi = srcHi `testBit` 63 
                 carryLo = srcLo `testBit` 63
+        len = byteArrayLength b
 {-
 	const uint64_t gf_mask = cpu_to_le64(0x8000000000000000ULL);
 	uint64_t r = ((a->q[1] & gf_mask) ? cpu_to_le64(0x87) : 0);