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