Remove DRBG dependency

2 files changed, 31 insertions, 15 deletions

diff --git a/src/Verismith/Fuzz.hs b/src/Verismith/Fuzz.hs
index 10fbfa8..20dc13c 100644
--- a/src/Verismith/Fuzz.hs
+++ b/src/Verismith/Fuzz.hs
@@ -36,7 +36,6 @@ import           Control.Monad.IO.Class
 import           Control.Monad.Reader
 import           Control.Monad.State.Strict
 import           Control.Monad.Trans.Control (MonadBaseControl)
-import qualified Crypto.Random.DRBG          as C
 import           Data.ByteString             (ByteString)
 import           Data.List                   (nubBy, sort)
 import           Data.Maybe                  (catMaybes, fromMaybe, isNothing)
@@ -64,6 +63,7 @@ import           Verismith.Tool.Internal
 import           Verismith.Tool.Yosys
 import           Verismith.Verilog.AST
 import           Verismith.Verilog.CodeGen
+import Verismith.Utils (generateByteString)
 
 data FuzzOpts = FuzzOpts { _fuzzOptsOutput      :: !(Maybe FilePath)
                          , _fuzzOptsForced      :: !Bool
@@ -308,7 +308,7 @@ simulation src = do
     datadir <- fmap _fuzzDataDir askOpts
     synth    <- passedSynthesis
     counterEgs <- failEquivWithIdentityCE
-    vals     <- liftIO $ generateByteString 20
+    vals     <- liftIO $ generateByteString Nothing 32 20
     ident    <- liftSh $ sim datadir vals Nothing defaultIdentitySynth
     resTimes <- liftSh $ mapM (sim datadir vals (justPass $ snd ident)) synth
     resTimes2 <- liftSh $ mapM (simCounterEg datadir) counterEgs
@@ -338,19 +338,6 @@ simulation src = do
             runSimIcEC datadir defaultIcarus a src b (Just ident)
       where dir = fromText $ "countereg_sim_" <> toText a
 
--- | Generate a specific number of random bytestrings of size 256.
-randomByteString :: C.CtrDRBG -> Int -> [ByteString] -> [ByteString]
-randomByteString gen n bytes
-    | n == 0    = ranBytes : bytes
-    | otherwise = randomByteString newGen (n - 1) $ ranBytes : bytes
-    where Right (ranBytes, newGen) = C.genBytes 32 gen
-
--- | generates the specific number of bytestring with a random seed.
-generateByteString :: Int -> IO [ByteString]
-generateByteString n = do
-    gen <- C.newGenIO :: IO C.CtrDRBG
-    return $ randomByteString gen n []
-
 failEquivWithIdentity :: (MonadSh m) => Fuzz m [SynthResult]
 failEquivWithIdentity = filter withIdentity . _fuzzSynthResults <$> get
   where
diff --git a/src/Verismith/Utils.hs b/src/Verismith/Utils.hs
new file mode 100644
index 0000000..1f5dd01
--- /dev/null
+++ b/src/Verismith/Utils.hs
@@ -0,0 +1,29 @@
+{-|
+Module      : Verismith
+Description : Verismith
+Copyright   : (c) 2020, Yann Herklotz
+License     : GPL-3
+Maintainer  : yann [at] yannherklotz [dot] com
+Stability   : experimental
+Portability : POSIX
+-}
+
+module Verismith.Utils
+  (generateByteString)
+where
+
+import System.Random (mkStdGen, newStdGen, randoms)
+import Data.ByteString (ByteString, pack)
+
+generateByteString :: (Maybe Int) -> Int -> Int -> IO [ByteString]
+generateByteString mseed size n = do
+    fmap pack . chunksOf size . take (size * n) . randoms <$>
+      case mseed of
+        Just seed' -> return $ mkStdGen seed'
+        Nothing    -> newStdGen
+  where
+    chunksOf i _ | i <= 0 = error $ "chunksOf, number must be positive, got " ++ show i
+    chunksOf i xs = repeatedly (splitAt i) xs
+    repeatedly _ [] = []
+    repeatedly f as = b : repeatedly f as'
+      where (b, as') = f as