-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 15 juil. 04, at 13:26, John Meacham wrote:
Perhaps I am just missing something, but a major piece of efficient array functionality seems to be missing. Namely the ability to efficiently copy spans of arrays into one another and/or compare spans of memory. (basically memcpy and memcmp from C).
memcpy is available in Foreign.Marshal.Utils: copyBytes :: Ptr a -> Ptr a -> Int -> IO () Copies the given number of bytes from the second area (source) into the first (destination);the copied areas may not overlap Here is the result of a quick try to implement fast copy using it and Data.Array.Storable: module FastArrrayCopy where import Data.Array.Storable import Foreign.Ptr import Foreign.Storable import Foreign.Marshal.Utils ( copyBytes ) fastArrayCopy :: (Storable e1, Ix i, Ix i1) => StorableArray i1 e1 -> i1 -> StorableArray i e -> i -> Int -> IO () fastArrayCopy src srcStart dest destStart count | destOffset + count > rangeSize (bounds dest) = error "Out of bounds" | otherwise = withStorableArray src $ \ pSrc -> withStorableArray dest $ \ pDest -> do dummy <- peek pSrc copyBytes (pDest `plusPtr` (destOffset * sizeOf dummy)) (pSrc `plusPtr` (srcOffset * sizeOf dummy)) (count * sizeOf dummy) where srcOffset = index (bounds src) srcStart destOffset = index (bounds dest) destStart main :: IO () main = do a <- newListArray (0, 100) ([0..] :: [Int]) a' <- newArray (0, 50) (42 :: Int) getElems a' >>= print copyRange a 10 a' 15 20 getElems a' >>= print It seems to work on GHC 6.2.1, though I did not made further tests than this main. Hope this helps, Jérémy. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (Darwin) iD8DBQFA9pK8JhPEcwATZDwRAhSnAJ9BELp+L/L2rFaYwFFzg/axQjEJ8wCcC+YV iN+XPdynHWROb3x27eVa5wE= =f5Vo -----END PGP SIGNATURE-----