Binary encode/decode of Fixed

binary.hs

-- run it like: 
-- stack ghc --package criterion -- binary.hs -Wall -O2 && ./binary
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE BangPatterns #-}
module Main where

import           Data.ByteString.Lazy (ByteString)
import           Data.Binary
import           Data.Fixed

import           Criterion.Main

{-# INLINE toPicos #-}
toPicos :: Pico -> Integer
toPicos (MkFixed x) = x

{-# INLINE fromPicos #-}
fromPicos :: Integer -> Pico
fromPicos = MkFixed

instance Binary (Fixed E12) where
  get = fromPicos <$> get
  put = put . toPicos

main :: IO ()
main = do
    let pico = 123 :: Pico
        !encodedPico = encode pico
    putStrLn $ "Encoded pico " ++ (show pico) ++ ": " ++ show encodedPico
    defaultMain
        [ bgroup "Pico"
          [ bench "encode" $ nf encode pico
          , bench "decode" $ nf (decode :: ByteString -> Pico) encodedPico ]
        ]

-- 700ns for a SINGLE fixed-point value!
--
-- Encoded pico 123.000000000000: "\SOH\SOH\NUL\NUL\NUL\NUL\NUL\NUL\NUL\ACK\NUL\176N+\222o"
-- benchmarking Pico/encode
-- time                 720.4 ns   (719.4 ns .. 721.7 ns)
--                      1.000 R²   (1.000 R² .. 1.000 R²)
-- mean                 719.7 ns   (719.0 ns .. 720.6 ns)
-- std dev              2.777 ns   (2.380 ns .. 3.290 ns)

-- benchmarking Pico/decode
-- time                 745.6 ns   (744.9 ns .. 746.3 ns)
--                      1.000 R²   (1.000 R² .. 1.000 R²)
-- mean                 745.6 ns   (744.7 ns .. 746.2 ns)
-- std dev              2.491 ns   (1.823 ns .. 4.192 ns)