hphp/hack/src/hhbc/unique_list.ml

   1 (**
   2  * Copyright (c) 2017, Facebook, Inc.
   3  * All rights reserved.
   4  *
   5  * This source code is licensed under the MIT license found in the
   6  * LICENSE file in the "hack" directory of this source tree.
   7  *
   8 *)
   9
  10 module WithValue(Value: Set.OrderedType) = struct
  11   module ValueSet = Set.Make (Value)
  12   type t = {
  13     unique_set : ValueSet.t;
  14     unique_list : Value.t list
  15   }
  16
  17   let empty = { unique_set = ValueSet.empty; unique_list = [] }
  18
  19   let add uniq_set item =
  20     if ValueSet.mem item uniq_set.unique_set then
  21       uniq_set
  22     else
  23       {
  24         unique_set = (ValueSet.add item uniq_set.unique_set);
  25         unique_list = item :: uniq_set.unique_list
  26       }
  27
  28   let items uniq_set =
  29     List.rev uniq_set.unique_list
  30
  31   let items_set uniq_set =
  32     uniq_set.unique_set
  33
  34   let remove item uniq_set =
  35     if ValueSet.mem item uniq_set.unique_set then
  36       {
  37         unique_set = (ValueSet.remove item uniq_set.unique_set);
  38         unique_list = List.filter (fun a -> a <> item) uniq_set.unique_list
  39       }
  40     else
  41       uniq_set
  42
  43   let diff s1 s2 =
  44     ValueSet.fold remove s2.unique_set s1
  45
  46   let cardinal uniq_set = ValueSet.cardinal uniq_set.unique_set
  47 end