From 0bb8daa7da52240a971a4ce83d97cfb62971ea78 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Roman=20Smr=C5=BE?= <roman.smrz@seznam.cz>
Date: Sun, 18 Oct 2026 16:52:41 +0200
Subject: Add crypto backend using various reference libraries

---
 src/crypto/reflibs/Crypto/Hash.hs | 80 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 src/crypto/reflibs/Crypto/Hash.hs

(limited to 'src/crypto/reflibs/Crypto/Hash.hs')

diff --git a/src/crypto/reflibs/Crypto/Hash.hs b/src/crypto/reflibs/Crypto/Hash.hs
new file mode 100644
index 0000000..36308f9
--- /dev/null
+++ b/src/crypto/reflibs/Crypto/Hash.hs
@@ -0,0 +1,80 @@
+module Crypto.Hash (
+    Digest,
+    Blake2b_256,
+
+    digestFromByteString,
+    hashInit,
+    hashUpdates,
+    hashFinalize,
+    hashDigestSize,
+) where
+
+import Control.DeepSeq
+import Control.Monad
+
+import Data.ByteArray
+import Data.ByteString (ByteString)
+import Data.ByteString qualified as BS
+import Data.ByteString.Unsafe
+
+import Foreign.C.Types
+import Foreign.ForeignPtr
+import Foreign.Marshal.Alloc
+import Foreign.Marshal.Utils
+import Foreign.Ptr
+import Foreign.Storable
+
+import System.IO.Unsafe
+
+
+newtype Digest a = Digest ByteString
+    deriving (Eq, Ord, NFData, ByteArrayAccess)
+
+data Context a = Context (ForeignPtr Blake2bContext)
+
+data Blake2bContext
+
+data Blake2b_256
+
+
+digestFromByteString :: ByteString -> Maybe (Digest Blake2b_256)
+digestFromByteString bs
+    | BS.length bs == digestSize = Just (Digest bs)
+    | otherwise                  = Nothing
+
+hashInit :: Context Blake2b_256
+hashInit = unsafePerformIO $ do
+    fctx <- mallocForeignPtrBytes stateSize
+    withForeignPtr fctx $ \ctx -> void $ cInit ctx (fromIntegral digestSize)
+    return $ Context fctx
+
+hashUpdates :: Context Blake2b_256 -> [ ByteString ] -> Context Blake2b_256
+hashUpdates (Context fbefore) updates = unsafePerformIO $ do
+    fafter <- mallocForeignPtrBytes stateSize
+    withForeignPtr fbefore $ \before ->
+        withForeignPtr fafter $ \after -> do
+            copyBytes after before stateSize
+            forM_ updates $ \update -> unsafeUseAsCStringLen update $ \( ptr, len ) -> do
+                void $ cUpdate after ptr (fromIntegral len)
+    return $ Context fafter
+
+hashFinalize :: Context Blake2b_256 -> Digest Blake2b_256
+hashFinalize (Context fctx) = unsafePerformIO $ do
+    bytes <- mallocBytes digestSize
+    withForeignPtr fctx $ \ctx ->
+        void $ cFinal ctx bytes (fromIntegral digestSize)
+    Digest <$> unsafePackMallocCStringLen ( bytes, digestSize )
+
+hashDigestSize :: Blake2b_256 -> Int
+hashDigestSize _ = fromIntegral digestSize
+
+digestSize :: Int
+digestSize = 32
+
+stateSize :: Int
+stateSize = fromIntegral $ unsafeDupablePerformIO $ peek cStateSize
+
+foreign import ccall unsafe "&blake2b_state_size" cStateSize :: Ptr CSize
+foreign import ccall unsafe "blake2b_init" cInit :: Ptr Blake2bContext -> CSize -> IO CInt
+foreign import ccall unsafe "blake2b_update" cUpdate :: Ptr Blake2bContext -> Ptr CChar -> CSize -> IO CInt
+foreign import ccall unsafe "blake2b_final" cFinal :: Ptr Blake2bContext -> Ptr CChar -> CSize -> IO CInt
-- 
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