1 files changed, 29 insertions, 10 deletions

diff --git a/VectorRing.hs b/VectorRing.hs
index 2ddac72..4362fa7 100644
--- a/VectorRing.hs
+++ b/VectorRing.hs
@@ -1,17 +1,36 @@
 module VectorRing where
 
-import Data.Vector.Unboxed.Mutable
+import Data.Vector.Storable.Mutable
 import RingBuffer
 
+import Foreign.Ptr
+import Foreign.ForeignPtr
+import Foreign.Storable
+import GHC.Exts (RealWorld)
+
+data Point = Point
+    { pointX :: Double
+    , pointY :: Double
+    }
+ deriving (Eq,Ord,Show)
+
+instance Storable Point where
+    sizeOf _ = 2 * sizeOf (0::Double)
+    alignment _ = alignment (0::Double)
+    peek ptr = Point <$> peek (castPtr ptr) <*> peekElemOff (castPtr ptr) 1
+    poke ptr (Point x y) = do poke (castPtr ptr) x
+                              pokeElemOff (castPtr ptr) 1 y
+
 -- | Typical usage:
 --
--- > ringBuffer <- newRing capacity (VectorRing.new capacity)
-new :: Unbox a => Int -> IO (TargetBuffer a)
-new sz = do
-    v <- unsafeNew sz
-    return () :: IO ()
-    return TargetBuffer
-        { syncBuffer   = \_ -> return ()
-        , updateBuffer = \i u -> write v i u
-        }
+-- > v <- unsafeNew capacity
+-- > ringBuffer <- newRing capacity (VectorRing.new v)
+new :: Storable a => MVector RealWorld a -> IO (TargetBuffer a)
+new v = return TargetBuffer
+            { syncBuffer   = \_ -> return ()
+            , updateBuffer = \i u -> write v i u
+            }
 
+withData :: Storable a => MVector RealWorld a -> (Int -> Ptr a -> IO b) -> IO b
+withData v f = let (fptr,len) = unsafeToForeignPtr0 v
+               in withForeignPtr fptr $ f len