[Libguestfs] [PATCH 1/3] mllib: Add sort_uniq function.

[Denis V. Lunev]

On 11/18/2015 01:03 AM, Richard W.M. Jones wrote:
> This is copied from supermin.
> ---
>   mllib/common_utils.ml  | 16 ++++++++++++++++
>   mllib/common_utils.mli |  6 ++++++
>   2 files changed, 22 insertions(+)
>
> diff --git a/mllib/common_utils.ml b/mllib/common_utils.ml
> index 13e9256..5fb7183 100644
> --- a/mllib/common_utils.ml
> +++ b/mllib/common_utils.ml
> @@ -267,6 +267,22 @@ let rec assoc ?(cmp = compare) ~default x = function
>     | (y, y') :: _ when cmp x y = 0 -> y'
>     | _ :: ys -> assoc ~cmp ~default x ys
>   
> +let uniq ?(cmp = Pervasives.compare) xs =
> +  let rec loop acc = function
> +    | [] -> acc
> +    | [x] -> x :: acc
> +    | x :: (y :: _ as xs) when cmp x y = 0 ->
> +       loop acc xs
> +    | x :: (y :: _ as xs) ->
> +       loop (x :: acc) xs
> +  in
> +  List.rev (loop [] xs)
> +
> +let sort_uniq ?(cmp = Pervasives.compare) xs =
> +  let xs = List.sort cmp xs in
> +  let xs = uniq ~cmp xs in
> +  xs
> +
>   let may f = function
>     | None -> ()
>     | Some x -> f x
> diff --git a/mllib/common_utils.mli b/mllib/common_utils.mli
> index 44b8c93..68f7988 100644
> --- a/mllib/common_utils.mli
> +++ b/mllib/common_utils.mli
> @@ -124,6 +124,12 @@ val assoc : ?cmp:('a -> 'a -> int) -> default:'b -> 'a -> ('a * 'b) list -> 'b
>   (** Like {!List.assoc} but with a user-defined comparison function, and
>       instead of raising [Not_found], it returns the [~default] value. *)
>   
> +val uniq : ?cmp:('a -> 'a -> int) -> 'a list -> 'a list
> +  (** Uniquify a list (the list must be sorted first). *)
> +
> +val sort_uniq : ?cmp:('a -> 'a -> int) -> 'a list -> 'a list
> +  (** Sort and uniquify a list. *)
> +
>   val may : ('a -> unit) -> 'a option -> unit
>   (** [may f (Some x)] runs [f x].  [may f None] does nothing. *)
>   
adding roman to CC: