test.hs

{-# Language BangPatterns #-}
module Main where

import Data.Binary.Get
import Data.Word
import Data.Bits
import Data.List (foldl')
import Test.BenchPress
import Control.Monad
import qualified Data.ByteString.Lazy as BS

csum16 :: BS.ByteString -> Word16
csum16 s = rotate $ trunc $ (foldl' (\acc w -> acc + fromIntegral w) 0) words
    where
        words = flip runGet s (replicateM (fromIntegral (BS.length s `div` 2)) $ getWord16le)
        trunc :: Word32 -> Word16
        trunc w = fromIntegral $ complement $ (w .&. 0xFFFF) + (w `shiftR` 16)
 
        rotate :: Word16 -> Word16
        rotate x = x `rotateL` 8
        {-# INLINE rotate #-}
{-# INLINE csum16 #-}
 
iter :: [BS.ByteString] -> IO Word16
iter samples = let !s = sum $ take 10000 $ map csum16 $ cycle samples
                in return s

main :: IO ()
main = do
    let samples = map (BS.replicate 512) [0 .. 255]
    print "start"
    samples `seq` bench 100 (iter samples)