more minor things

src/Leopard/Binding.hs

@@ -9,8 +9,10 @@ module Leopard.Binding where
 import Data.Word
 import Data.Array
 import Data.Maybe
+import Data.IORef
 
 import Control.Monad
+import System.IO.Unsafe
 
 import Foreign.C
 import Foreign.C.Types
@@ -64,14 +66,28 @@ decodeLeopardResult result = case result of
 --------------------------------------------------------------------------------
 -- * C++ bindings
 
-{-# NOINLINE initLeopard #-}
-initLeopard :: IO ()
-initLeopard = do
+{-# NOINLINE initLeopard' #-}
+initLeopard' :: IO ()
+initLeopard' = do
   res <- cpp_leo_init leo_VERSION
   if (res == 0)
     then return ()
     else fail "Leopard initialization failed"
 
+-- I just hope it's not a per-thread initialization... :)
+-- (then we would need `Map ThreadId Bool`)
+{-# NOINLINE theInitializedFlag #-}
+theInitializedFlag :: IORef Bool
+theInitializedFlag = unsafePerformIO (newIORef False)
+
+{-# NOINLINE initLeopard #-}
+initLeopard :: IO ()
+initLeopard = do
+  ok <- readIORef theInitializedFlag
+  unless ok $ do
+    initLeopard'
+    writeIORef theInitializedFlag True
+
 withLeopard :: IO a -> IO a
 withLeopard action = do
   initLeopard
@@ -149,14 +165,14 @@ unsafeDecodeIO :: ECParams -> Array Int (Maybe ByteString) -> IO (Either Leopard
 unsafeDecodeIO ecParams@(ECParams k n) mbChunks = do
   let m = n - k
   work_cnt <- cpp_leo_decode_work_count (fromIntegral k) (fromIntegral m)
-  when (work_cnt == 0) $ fail "edeode: `leo_decode_work_count` claims invalid input"
+  when (work_cnt == 0) $ fail "decode: `leo_decode_work_count` claims invalid input"
   let work_cnt_int = fromIntegral work_cnt :: Int
 
   let nchunks       = arrayLength mbChunks
   let sizes         = map B.length (catMaybes $ elems mbChunks)
   let mb_chunk_size = isUniformList sizes
 
-  unless (n == nchunks)         $ fail "encode: we need exactly N encoded chunks"    
+  unless (n == nchunks)         $ fail "decode: we need exactly N encoded chunks"    
   unless (isJust mb_chunk_size) $ fail "decode: chunk size must be uniform"
 
   let chunk_size = fromJust mb_chunk_size

src/Leopard/Misc.hs

@@ -108,6 +108,10 @@ maskRandomly k arr = do
   return $ listArray (u,v) 
     [ if b then Just x else Nothing | (x,b) <- zip (elems arr) (elems mask) ]
 
+-- | There will be @k@ @Nothing@-s in the resulting list
+maskListRandomly :: Int -> [a] -> IO [Maybe a]
+maskListRandomly k xs = elems <$> maskRandomly k (arrayFromList xs)
+
 -- | @randomBoolMask n k@ will give you @k@ falses and @(n-k)@ trues
 randomBoolMask :: Int -> Int -> IO (Array Int Bool)
 randomBoolMask n k = go k trues where

src/Leopard/Types.hs

@@ -24,8 +24,8 @@ data ECParams = ECParams
   deriving (Eq,Show)
 
 -- | Number of \"parity\" chunks
-ecM :: ECParams -> Int           
-ecM params = _ecN params - _ecK params
+_ecM :: ECParams -> Int           
+_ecM params = _ecN params - _ecK params
 
 isValidECParams :: ECParams -> Bool
 isValidECParams (ECParams k n) = and