1 {-# LANGUAGE ExistentialQuantification #-}
2 module Mate.MemoryManager ( ) where
4 import qualified Foreign.Marshal.Alloc as Alloc
6 import Foreign.Storable
11 import Control.Monad.State
15 class AllocationManager a where
16 mallocBytes :: a -> Int -> (a,Ptr b)
18 data TwoSpace = TwoSpace { fromBase :: IntPtr,
22 fromExtreme :: IntPtr,
25 mallocBytes' :: Int -> State TwoSpace (Ptr b)
26 mallocBytes' bytes = do state <- get
27 let end = (toHeap state) + (ptrToIntPtr $ nullPtr `plusPtr` bytes) -- not really? FUUU
28 -- actually i would like to use an existential within TwoSpace but this requires
29 -- pattern matchingt at call site http://stackoverflow.com/questions/10192663/why-cant-existential-types-use-record-syntax which is i think even slower.
30 if end <= toExtreme state then alloc state end else fail
31 where alloc :: TwoSpace -> IntPtr -> State TwoSpace (Ptr b)
32 alloc state end = do let ptr = toHeap state
33 put $ state { toHeap = end }
34 return $ intPtrToPtr ptr
35 fail = error "no space left in two space (mallocBytes')"
37 -- here its time for monadtransformer :)
38 evacuate :: [Ptr a] -> State TwoSpace (IO (HashTable (Ptr a) (Ptr a)))
42 initTwoSpace :: Int -> IO TwoSpace
43 initTwoSpace size = do printf "initializing TwoSpace memory manager with %d bytes." size
44 fromSpace <- Alloc.mallocBytes size
45 toSpace <- Alloc.mallocBytes size
46 if fromSpace /= nullPtr && toSpace /= nullPtr
47 then return $ buildToSpace fromSpace toSpace
48 else error "Could not initialize TwoSpace memory manager (malloc returned null ptr)"
49 where buildToSpace from to = let fromBase' = ptrToIntPtr from
50 toBase' = ptrToIntPtr to
51 fromExtreme' = ptrToIntPtr $ from `plusPtr` size
52 toExtreme' = ptrToIntPtr $ to `plusPtr` size
53 in TwoSpace { fromBase = fromBase', toBase = toBase',
54 fromHeap = fromBase', toHeap = toBase',
55 fromExtreme = fromExtreme', toExtreme = toExtreme' }