Some binary magic

1 files changed, 25 insertions, 1 deletions

diff --git a/src/Binary.hs b/src/Binary.hs
index 4575c49..fbf0a07 100644
--- a/src/Binary.hs
+++ b/src/Binary.hs
@@ -1,14 +1,17 @@
 module Binary
   ( toBinary
   , fromBinary
+  , toBitString
+  , fromBitString
   ) where
 
 import           Control.Applicative
+import qualified Data.BitString                as Bit
 import           Data.Char
 import           Helper
 
 toBinary :: Expression -> String
-toBinary (Bruijn      x        ) = (replicate x '1') ++ "0"
+toBinary (Bruijn      x        ) = (replicate (x + 1) '1') ++ "0"
 toBinary (Abstraction exp      ) = "00" ++ toBinary exp
 toBinary (Application exp1 exp2) = "01" ++ (toBinary exp1) ++ (toBinary exp2)
 
@@ -25,3 +28,24 @@ fromBinary = foldr
   showsBin n x = if n == 0
     then id
     else let (x', b) = divMod x 2 in showsBin (n - 1) x' . (intToDigit b :)
+
+-- TODO: Fix weird endianess things
+padBitList :: [Bool] -> [Bool]
+padBitList lst | length lst `mod` 8 == 0 = lst
+               | otherwise               = padBitList ([False] ++ lst)
+
+toBitString :: String -> Bit.BitString
+toBitString = Bit.fromList . padBitList . map
+  (\case
+    '0' -> False
+    '1' -> True
+  )
+
+fromBitString :: Bit.BitString -> String
+fromBitString =
+  map
+      (\case
+        False -> '0'
+        True  -> '1'
+      )
+    . Bit.toList