src/DNS.hs

   1 module DNS (
   2   normalize
   3   )
   4 where
   5
   6 import qualified Data.ByteString.Char8 as BS (
   7   append,
   8   last,
   9   map,
  10   pack )
  11 import Data.Char (toLower)
  12 import Network.DNS.Types (Domain)
  13
  14 -- | Normalize the given name by lowercasing and appending a trailing
  15 --   dot (the root) if necessary.
  16 normalize :: Domain -> Domain
  17 normalize = normalize_case . normalize_root
  18
  19
  20 normalize_root :: Domain -> Domain
  21 normalize_root d
  22   | BS.last d == '.' = d
  23   | otherwise = d `BS.append` trailing_dot
  24     where
  25       trailing_dot = BS.pack "."
  26
  27
  28 normalize_case :: Domain -> Domain
  29 normalize_case = BS.map toLower