(*
copyright (c) 2013-2015, simon cruanes
all rights reserved.

redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.  redistributions in binary
form must reproduce the above copyright notice, this list of conditions and the
following disclaimer in the documentation and/or other materials provided with
the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*)

(** {1 Map specialized for Int keys}

{b status: unstable}
@since 0.10 *)

type 'a t

val empty : 'a t

val singleton : int -> 'a -> 'a t

val doubleton : int -> 'a -> int -> 'a -> 'a t

val mem : int -> _ t -> bool

val find : int -> 'a t -> 'a option

val find_exn : int -> 'a t -> 'a
(** Same as {!find} but unsafe
    @raise Not_found if key not present *)

val add : int -> 'a -> 'a t -> 'a t

val remove : int -> 'a t -> 'a t

val update : int -> ('a option -> 'a option) -> 'a t -> 'a t

val cardinal : _ t -> int

val iter : (int -> 'a -> unit) -> 'a t -> unit

val fold : (int -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b

val choose : 'a t -> (int * 'a) option

val choose_exn : 'a t -> int * 'a

val union : (int -> 'a -> 'a -> 'a) -> 'a t -> 'a t -> 'a t

val inter : (int -> 'a -> 'a -> 'a) -> 'a t -> 'a t -> 'a t

(** {2 Whole-collection operations} *)

type 'a sequence = ('a -> unit) -> unit
type 'a gen = unit -> 'a option

val add_list : 'a t -> (int * 'a) list -> 'a t

val of_list : (int * 'a) list -> 'a t

val to_list : 'a t -> (int * 'a) list

val add_seq : 'a t -> (int * 'a) sequence -> 'a t

val of_seq : (int * 'a) sequence -> 'a t

val to_seq : 'a t -> (int * 'a) sequence

val keys : _ t -> int sequence

val values : 'a t -> 'a sequence


(** Helpers *)

val highest_bit : int -> int

type 'a tree = unit -> [`Nil | `Node of 'a * 'a tree list]

val as_tree : 'a t -> [`Node of int * int | `Leaf of int * 'a ] tree