ByteSum.hs

module Main where

import System.Environment (getArgs)
import qualified Data.ByteString.Lazy as L
import Data.Word

{-
- Test to see how fast we can process an 1GB binary file.
- From the blog post: http://jvns.ca/blog/2014/05/12/computers-are-fast/
-
-}

-- Result: stack space overflow...
addBytes :: [Word8] -> Word8
addBytes [] = 0
addBytes (x:xs) = x + addBytes xs

-- Result: stack space overflow...
addBytes' :: [Word8] -> Word8
addBytes' = foldr (+) 0

-- Result: 18 seconds
addBytes'' :: [Word8] -> Word8
addBytes'' = sum

main :: IO ()
main = do
        args <- getArgs
        let filename = head args
        fc <- L.readFile filename
        print $ addBytes'' $ L.unpack fc