[Haskell]バイナリ操作の取っ掛かり

binary.hs

{-# LANGUAGE CPP, TemplateHaskell #-}
-----------------------------------------------------------------------------
--
-- Module      :  Main
-- Copyright   :
-- License     :  Public Domain
--
-- Maintainer  :
-- Stability   :
-- Portability :
--
-- |
--
-----------------------------------------------------------------------------

module Main (
    main
) where

import Control.Monad (unless)
import Data.List (stripPrefix)
import System.Exit (exitFailure)
import Test.QuickCheck.All (quickCheckAll)
import qualified Data.ByteString as B
import Data.Char
import Text.Printf
import Data.Bits

hex1 n
    |  0 <= n && n <=  9 = chr ((ord '0') + n)
    | 10 <= n && n <= 15 = chr ((ord 'a') + (n - 0xa))
hex2 n = [hex1 (shiftR n 4)] ++ [hex1 (n .&. 0xf)]

prop_hex1 n = [hex1 m] == printf "%x" m where m = n .&. 0xf
prop_hex2 n = hex2 m == printf "%02x" m where m = n .&. 0xff

-- Hello World
exeMain = do
    bin <- B.readFile "test"
    putStrLn $ "len " ++ (show $ B.length bin)

-- Entry point for unit tests.
testMain = do
    allPass <- $quickCheckAll -- Run QuickCheck on all prop_ functions
    unless allPass exitFailure

-- This is a clunky, but portable, way to use the same Main module file
-- for both an application and for unit tests.
-- MAIN_FUNCTION is preprocessor macro set to exeMain or testMain.
-- That way we can use the same file for both an application and for tests.
#ifndef MAIN_FUNCTION
#define MAIN_FUNCTION exeMain
#endif
main = MAIN_FUNCTION