Bulat is right about making Block's fields strict.
-- | Get the offsets between entries in a list getSizes :: [Integer] -> [Integer] getSizes (x:y:[]) = [y - x] getSizes (x:y:ys) = (y - x):(getSizes (y:ys))
You should change the first part to add maxSize:
getSizes :: [Integer] -> [Integer] getSizes (x:y:[]) = [y - x,maxSize] getSizes (x:y:ys) = (y - x):(getSizes (y:ys))
This avoids the ugly use of (++) below. Note that appending to a singly linked list is a bad "code smell":
-- | creates and returns a list of Blocks, given a file's content. blocks :: ByteString -> [Block] blocks s = zipWith (Block) offsets sizes where offsets = getOffsets s sizes = getSizes offsets
main :: IO () main = do args <- getArgs content <- B.readFile (args!!0) printf "%s" $ unlines $ map (show) (sort $! blocks content) \end{code}
I think the printf "%s" should be replaced by putStr or putStrLn. The print is forcing the unlines which forces the map which forces the result of sort. The ($!) is nearly pointless...it forces only the first cons (:) cell in the list. The sort starts comparing the output of blocks by applying compare. The compare forces the snd part of the part from the zipWith, which is the sizes. The size values force the values in the offsets in the fst part of the pair. The fst part of the pair was actually a lazy thunk returned by the C8.readInteger function. But these do not build up since the are indirectly getting forced during the sorting routine. Hmmm....no quick fix. -- Chris