> module Passwd (id_to_name, readfile) where

> import Library

> import Exception


Given an ID and a list of strings representing a parsed file in the
same format as /etc/{passwd,group} return the {user,group}name

> id_to_name :: Int -> [String] -> String
> id_to_name id [] = show id
> id_to_name id (s:ss) = if num_id == show id then str_id
>                                             else id_to_name id ss
>  where (str_id, s1) = takeDropUntil ((==) ':') s
>        s2 = dropUntil ((==) ':') s1
>        num_id = takeUntil ((==) ':') s2


Read in a file and split it into lines. Return [] if we get an error.

> readfile :: FilePath -> IO [String]
> readfile fp = catchAllIO (do contents <- readFile fp
>                              return $ splitlines contents)
>                          (\_ -> return [])


Split a file into lines

> splitlines :: String -> [String]
> splitlines [] = []
> splitlines xs = ys:splitlines zs
>  where (ys, zs) = (takeDropUntil ((==) '\n') xs)