@hackage binary-file0.15.18

See example directory's sample code.

runghc -XQuasiQuotes -XTypeFamilies -XFlexibleInstances exam.hs some.bmp

exam.hs:

 import File.Binary
 import File.Binary.Instances
 import File.Binary.Instances.LittleEndian
 import System.Environment
 import Data.ByteString.Lazy as BSL

 main = do
	[inf] <- getArgs
   cnt <- BS.readFile inf
	let Right (bmp, rest) = fromBinary () cnt :: (Bitmap, String)
	print bmp

 instance Field (Int, Int, Int) where
    type FieldArgument (Int, Int, Int) = ()
    fromBinary _ s = do
        (b, rest) <- fromBinary 1 s
        (g, rest') <- fromBinary 1 rest
        (r, rest'') <- fromBinary 1 rest' in
        return ((b, g, r), snd $ getBytes 1 1 rest'')
    toBinary _ (b, g, r) = do
        b' <- toBinary 1 b
        g' <- toBinary 1 g
        r' <- toBinary 1 r
        return $ concatBinary [b', g', r', makeBinary $ BSL.singleton 0]

 [binary|

 Bitmap

 deriving Show

 2: "BM"
 4: file_size
 2: 0
 2: 0
 4: offset

 4: 40
 4: width
 4: height
 2: 1
 2: bits_per_pixel
 4: compression
 4: image_size
 4: resolutionH
 4: resolutionV
 4: color_num
 4: important_color_num
 ((), Just color_num)[OPENBRACKET](Int, Int, Int)[CLOSEBRACKET]: colors
 ((), image_size)[OPENBRACKET]String[CLOSEBRACKET]: image

 |]