crc32.hs

import           Control.Exception (evaluate)
import           Control.Monad (forM_)
import           Control.Monad (replicateM, forM)
import qualified Data.ByteString.Lazy as BS
import qualified Data.Digest.CRC32
import qualified Data.Digest.Pure.CRC32
import           System.Environment (getArgs)
import qualified System.Random.MWC as MWC
import           Data.Binary (encodeFile, decodeFile)
import           Data.Word (Word32)

randomByteString
  :: MWC.GenIO
  -> Int
  -- ^ Desired length
  -> IO BS.ByteString
randomByteString gen n = do
  bytes <- replicateM n $ MWC.uniform gen
  return $ BS.pack bytes

bench
  :: (BS.ByteString -> Word32)
  -- ^ CRC32 function
  -> [BS.ByteString] -> IO ()
bench digest bss = do
  forM_ bss $ \bs -> do
    forM_ [1..1000] $ \n -> do
      evaluate $ digest $ BS.cons (fromIntegral n) bs

main :: IO ()
main = do
  args <- getArgs
  case args of
    ["generate"] -> do
      gen <- MWC.create
      bss1mB <- forM (replicate 10 1000000) $ randomByteString gen
      encodeFile "data" bss1mB
    ["hask"] -> do
      bss <- decodeFile "data"
      bench Data.Digest.Pure.CRC32.crc32 bss
    ["c"] -> do
      bss <- decodeFile "data"
      bench Data.Digest.CRC32.crc32 bss