base64 encoder and decoder (text-only)

2 files changed, 46 insertions, 1 deletions

diff --git a/README.md b/README.md
index 711c9ba..e8f9124 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,3 @@
-# Miguel's Haskell Collections
+# Miguel's Haskell Collection
 
 A collection of some small haskell sources of mine.
diff --git a/base64/base64.hs b/base64/base64.hs
new file mode 100644
index 0000000..13f12bb
--- /dev/null
+++ b/base64/base64.hs
@@ -0,0 +1,45 @@
+--
+-- Miguel's Naive
+-- Base64 Encoder -- Coded on a winter afterfnoon on 19th Feb 2018 A.D.
+--                   to fully understand base64 encoding and play with 
+--                   haskell, which is always an indisputable pleasure.
+--
+--                   The following lines were written in full awareness 
+--                   that 'libraries' for this purpose, which perform way 
+--                   better, are in existence.
+--
+-- Coded in big anger due to nick's stories about saving his binary 
+-- format, encrypted passwords in an ascii config file, featuring 
+-- strange letters and characters.
+-- 
+-- Example Usage: echo "just testing" | stack runghc base64.hs  | stack runghc base64 -- -d
+-- (You can cross check with base64 / base64 -d) 
+
+import System.Environment
+import qualified Data.List.Split as T
+import qualified Data.List as L
+import qualified Data.Map.Strict as M
+import qualified Data.ByteString.Lazy as B
+import Text.Printf
+import Data.Maybe
+import Data.Char
+import Control.Monad
+
+main = do args<-getArgs
+          if length args == 0 then go encode64 
+          else when (args!!0 == "-d") $ go decode64
+          where go f = getContents >>= putStr.(++"\n").f
+
+fromBase64 x  = (['A'..'Z']++['a'..'z']++['0'..'9']++['+','/']) !! x
+mapBase64     = M.fromList $ map (\x-> (fromBase64 x,x)) [0..63]
+binToDec      = sum . map (2^) . L.findIndices (=='1') . reverse 
+
+encode64 x = pad64 (length x) . map (fromBase64 . binToDec) . T.chunksOf 6 . 
+             concat . map (printf "%08b" ) $ x ++ cycle "\000"
+
+decode64 x = map (chr . binToDec) . T.chunksOf 8 . 
+             concat . map ( printf "%06b" . fromJust) . filter isJust . 
+             map (flip M.lookup mapBase64) $ x
+
+pad64 l = (++(take m ((cycle "=")))) . take ((l+m)*3 `div` 2 -3-m)
+          where m = mod (3 - mod l 3) 3