buggy prototype of bytestring to UInteger conversion

Hash2Pub/hashtest.hs

@@ -2,10 +2,14 @@
 module Foo where
 
 import Crypto.Hash
+import Data.Word
+import Data.Bits (shift)
+import Network.Socket (HostAddress6)
 import qualified Data.ByteString as BS
 import qualified Data.ByteString.Builder as BB
 import qualified Data.ByteString.Lazy as BL
 import qualified Data.ByteString.UTF8 as BSU
+import qualified Data.Binary.Strict.Get as BinGet
 import qualified Data.ByteArray as BA
 
 -- important: only works with strict ByteStrings
@@ -15,7 +19,8 @@ hashToShake128 string = hash bstr :: Digest (SHAKE128 128)
 
 -- TODO: type signature
 -- TODO: convert byte string to Integer (as separate function, useful for parsing later on)
-hashNodeID ipaddr@(a, b, _, _) domain vserver =
+hashNodeIDBS :: HostAddress6 -> String -> Word8 -> BS.ByteString
+hashNodeIDBS ipaddr@(a, b, _, _) domain vserver =
     hashIpaddrUpper `BS.append` hashID domain' `BS.append` hashIpaddLower
         where
             vsBS = BS.pack [vserver] -- attention: only works for vserver IDs up to 255
@@ -25,4 +30,40 @@ hashNodeID ipaddr@(a, b, _, _) domain vserver =
             hashID bstr = BS.pack . BA.unpack $ (hash bstr :: Digest (SHAKE128 128))
             (hashIpaddrUpper, hashIpaddLower) = BS.splitAt 64 $ hashID ipaddrNet
 
-testIDHash = hashNodeID (0x2001 + 0x16b8, 0x755a + 0xb1100, 0x7d6a + 0x12ab, 0xf0c5 + 0x386e) "example.com" 0
+
+--hashNodeID = byteStringToUInteger hashNodeIDBS
+
+
+-- | parses the bit pattern of a ByteString as an unsigned Integer in Big Endian order
+-- by iterating it byte-wise from the back and shifting the byte values according to their offset
+byteStringToUInteger :: BS.ByteString -> Integer
+byteStringToUInteger bs = sum $ parsedBytes 0 bs
+  where
+    parsedBytes :: Integer -> BS.ByteString -> [ Integer ]
+    parsedBytes offset bs = case BS.unsnoc bs of
+                           Nothing -> []
+                           Just (bs, w) -> parseWithOffset offset w : parsedBytes (offset+1) bs
+
+    parseWithOffset :: Integer -> Word8 -> Integer
+    parseWithOffset 0 word = toInteger word  -- a shift of 0 is always 0
+    parseWithOffset offset word = shift (toInteger word) 8*offset
+
+-- |Utility function creating a strict ByteString from [Word32],
+-- needed for encoding @HostAddress6@ as a ByteString
+--packW32 :: [ Word32 ] -> BS.ByteString
+--packW32 [] = BS.empty
+--packW32 xs = map BinGet.
+--
+--w32ToBSParser :: BinGet.Get [Word8]
+--w32ToBSParser = do
+--    a <- getWord8
+--    b <- getWord8
+--    c <- getWord8
+--    d <- getWord8
+--    return [a, b, c, d]
+
+
+--- test data ---
+
+testIDHash = hashNodeIDBS (0x2001 + 0x16b8, 0x755a + 0xb1100, 0x7d6a + 0x12ab, 0xf0c5 + 0x386e) "example.com" 0
+zweiHoch248 = BS.pack $ 1:replicate 31 0