Re: [PATCH master 4/9] htools: add a small module for crypto functions

[Iustin Pop]

On Wed, Feb 22, 2012 at 04:56:29PM +0100, Guido Trotter wrote:
> On Tue, Feb 21, 2012 at 13:21, Iustin Pop <ius...@google.com> wrote:
> > +-- | Computes the HMAC for a given key/test and salt.
> > +computeMac :: HashKey -> Maybe String -> String -> String
> > +computeMac key salt text =
> > +  concat . map (printf "%02x") . hmac_sha1 key $ text''
> > +    where text' = case salt of
> > +                    Nothing -> text
> > +                    Just salt' -> salt' ++ text
> > +          text'' = stringToWord8 text'
> > +
> 
> I tried simplifying computeMac: would this work:
> diff --git a/htools/Ganeti/Hash.hs b/htools/Ganeti/Hash.hs
> index e64d7a0..84739ae 100644
> --- a/htools/Ganeti/Hash.hs
> +++ b/htools/Ganeti/Hash.hs
> @@ -48,11 +48,8 @@ stringToWord8 = B.unpack . encodeUtf8 . T.pack
>  -- | Computes the HMAC for a given key/test and salt.
>  computeMac :: HashKey -> Maybe String -> String -> String
>  computeMac key salt text =
> -  concat . map (printf "%02x") . hmac_sha1 key $ text''
> -    where text' = case salt of
> -                    Nothing -> text
> -                    Just salt' -> salt' ++ text
> -          text'' = stringToWord8 text'
> +  concat . map (printf "%02x") . hmac_sha1 key $
> +    stringToWord8 $ maybe text (++ text) salt

Yes, very nice! Since stringToWord8 is a function, you can replace the
first $ you added with a '.'.

thanks!
iustin