1 files changed, 73 insertions, 0 deletions
diff --git a/src/Storage.hs b/src/Storage.hs
new file mode 100644
index 0000000..2697c39
--- /dev/null
+++ b/src/Storage.hs
@@ -0,0 +1,73 @@
+{-# LANGUAGE ForeignFunctionInterface #-}
+
+module Storage(
+    PrefStorage,
+    createStorage,
+    pokePref,
+    peekPref
+    ) where
+
+
+
+
+import Foreign
+import Foreign.C
+
+
+
+
+foreign import ccall "create_pref_array"
+    c_createPrefArray :: CInt -> CInt -> IO (Ptr PrefArray)
+
+foreign import ccall "free_pref_array"
+    c_freePrefArray :: CInt -> CInt -> Ptr PrefArray -> IO ()
+
+foreign import ccall "wrapper"
+    wrap :: (Ptr PrefArray -> IO ()) -> IO (FunPtr (Ptr PrefArray -> IO ()))
+
+foreign import ccall "poke_pref_array"
+    c_pokePrefArray :: CInt -> CInt -> Ptr PrefArray -> CInt -> CInt -> CInt -> IO ()
+
+foreign import ccall "peek_pref_array"
+    c_peekPrefArray :: CInt -> CInt -> Ptr PrefArray -> CInt -> CInt -> CInt -> IO CInt
+
+
+
+
+newtype PrefArray = PrefArray (Ptr PrefArray)
+
+data PrefStorage = PrefStorage { pointer      :: ForeignPtr PrefArray
+                               , numBallots   :: Int
+                               , sizeOfBallot :: Int }
+
+
+
+
+createStorage :: Int -> Int -> IO PrefStorage
+createStorage n s = do
+    x <- c_createPrefArray (fromIntegral n) (fromIntegral s)
+    f <- wrap (c_freePrefArray (fromIntegral n) (fromIntegral s))
+    y <- newForeignPtr f x
+    return (PrefStorage y n s)
+
+
+
+
+pokePref :: PrefStorage -> Int -> Int -> Int -> IO ()
+pokePref p n s r = do
+    let numBal = fromIntegral (numBallots p)
+        sizeBal = fromIntegral (sizeOfBallot p)
+        func a = c_pokePrefArray numBal sizeBal a (fromIntegral n) (fromIntegral s) (fromIntegral r)
+    withForeignPtr (pointer p) func
+
+
+
+
+peekPref :: PrefStorage -> Int -> Int -> Int -> IO Bool
+peekPref p n s r = do
+    let numBal = fromIntegral (numBallots p)
+        sizeBal = fromIntegral (sizeOfBallot p)
+        func a = c_peekPrefArray numBal sizeBal a (fromIntegral n) (fromIntegral s) (fromIntegral r)
+    result <- withForeignPtr (pointer p) func
+    return (result /= 0)
+