+{-# LANGUAGE ScopedTypeVariables #-}
+module GC
+ ({- dont export generic versions for high performance ;-) -}) where
+
+import Control.Monad
+
+--import Data.Foldable hiding (mapM_)
+
+import Foreign.Ptr
+import Foreign.Marshal.Alloc
+import Foreign.Marshal.Array
+import Foreign.Storable
+import GHC.Int
+
+import qualified Data.Set as S
+import Text.Printf
+
+class (Eq a, Ord a) => RefObj a where
+ payload :: a -> IO IntPtr
+ refs :: a -> IO [a]
+ marked :: a -> IO Bool
+ mark :: a -> IO ()
+ unmark :: a -> IO ()
+
+-- TODO hs: wtf? i am failing to create a printable class with superclass refobj??
+--class RefObj a => PrintableRefObj a where
+-- printRef :: a -> IO ()
+
+class PrintableRef a where
+ printRef :: a -> IO ()
+
+instance RefObj (Ptr a) where
+ payload = return . ptrToIntPtr
+ refs = unpackRefs . castPtr
+ marked = markedRef
+ mark = markRef (0x1::Int32)
+ unmark = markRef (0x0::Int32)
+
+instance PrintableRef (Ptr a) where
+ printRef = printRef'
+
+
+idOff = 0x0
+numberOfObjsOff = 0x4
+fieldsOff = 0xC
+markedOff = 0x8
+
+unpackRefs :: Ptr Int32 -> IO [Ptr b]
+unpackRefs ptr = do --dereference number of objs; mark field skipped via fieldsOffset
+ numberOfObjs <- peekByteOff ptr numberOfObjsOff :: IO Int32
+ mapM (peekElemOff (ptr `plusPtr` fieldsOff)) [0..fromIntegral $ numberOfObjs-1]
+
+markedRef :: Ptr a -> IO Bool
+markedRef ptr = liftM ((/=0) . fromIntegral) (peekByteOff ptr markedOff :: IO Int32)
+
+markRef :: Int32 -> Ptr a -> IO ()
+markRef val ptr = pokeByteOff ptr markedOff val
+
+printRef' :: Ptr a -> IO ()
+printRef' ptr = do printf "obj 0x%08x\n" =<< (peekByteOff ptr idOff :: IO Int32)
+ printf "children 0x%08x\n" =<< (peekByteOff ptr numberOfObjsOff :: IO Int32)
+ printf "marked 0x%08x\n\n" =<< (peekByteOff ptr markedOff :: IO Int32)
+
+-- | Generically marks a graph (can be used to set mark bit and reset mark bit at the same time
+-- using customized loopcheck and marker funcs (i.e. to set the bit check on ==1 and on ==0 otherwise)
+-- Furthermore it produces a list of visited nodes (this can be all live one (or dead on respectively)
+markTree'' :: RefObj a => (a -> IO Bool) -> (a -> IO ()) -> [a] -> a -> IO [a]
+markTree'' loopcheck marker ws root = do loop <- loopcheck root
+ if loop then return ws else liftM (root :) continue
+ where continue = marker root >> refs root >>= foldM (markTree'' loopcheck marker) ws
+
+-- | For debugging only (implements custom loop check with Data.Set!)
+traverseIO :: RefObj o => (o -> IO ()) -> o -> IO ()
+traverseIO f = void . traverseIO' f S.empty
+
+traverseIO' :: RefObj a => (a -> IO ()) -> S.Set a -> a -> IO (S.Set a)
+traverseIO' f ws root = if S.member root ws then f root >> return ws
+ else f root >> refs root >>= cont
+ where cont = foldM (\ws x -> do let ws' = S.insert x ws
+ traverseIO' f ws' x) ws'
+ ws' = S.insert root ws
+
+markTree :: RefObj a => a -> IO ()
+markTree root = marked root >>= (`unless` continue)
+ where continue = mark root >> refs root >>= mapM_ markTree
+
+printTree :: Ptr a -> IO ()
+printTree = traverseIO printRef'
+
+
+emptyObj id = do mem <- mallocBytes 0xC
+ pokeArray mem [id,0,0::Int32]
+ return mem
+
+twoRefs = do mem <- mallocBytes 0x14
+ -- idOfObj; numberofObj; marked waste memory Int32
+ pokeArray mem [0::Int32,2,0]
+ obj1 <- emptyObj 1
+ obj2 <- emptyObj 2
+ pokeByteOff mem 0xC obj1
+ pokeByteOff mem 0x10 obj2
+ return mem
+
+cyclR = do mem <- mallocBytes 0x18
+ pokeArray mem [0::Int32,3,0]
+ obj1 <- emptyObj 1
+ obj2 <- emptyObj 2
+ pokeByteOff mem 0xC obj1
+ pokeByteOff mem 0x10 obj2
+ pokeByteOff mem 0x14 mem
+ return mem
+
+test objr = do twoRefs <- objr
+ putStrLn "initial:\n"
+ printTree twoRefs
+ lifeRefs <- markTree'' marked mark [] twoRefs
+ putStrLn "life refs: \n"
+ print lifeRefs
+ --forM lifeRefs printRef'
+ putStrLn "after marking\n"
+ printTree twoRefs
+ markTree'' (liftM not . marked) unmark [] twoRefs
+ putStrLn "after unmarking\n"
+ printTree twoRefs
projects / mate.git / commitdiff