(*****************************************************************************)
(*                                                                           *)
(* Open Source License                                                       *)
(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com>     *)
(*                                                                           *)
(* Permission is hereby granted, free of charge, to any person obtaining a   *)
(* copy of this software and associated documentation files (the "Software"),*)
(* to deal in the Software without restriction, including without limitation *)
(* the rights to use, copy, modify, merge, publish, distribute, sublicense,  *)
(* and/or sell copies of the Software, and to permit persons to whom the     *)
(* Software is furnished to do so, subject to the following conditions:      *)
(*                                                                           *)
(* The above copyright notice and this permission notice shall be included   *)
(* in all copies or substantial portions of the Software.                    *)
(*                                                                           *)
(* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR*)
(* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,  *)
(* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL   *)
(* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER*)
(* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING   *)
(* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER       *)
(* DEALINGS IN THE SOFTWARE.                                                 *)
(*                                                                           *)
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type n = Natural_tag
type z = Integer_tag
type 't num = Z.t

let compare x y = Z.compare x y

let zero = Z.zero
let zero_n = Z.zero

let to_string x = Z.to_string x
let of_string s = try Some (Z.of_string s) with _ -> None

let to_int64 x = try Some (Z.to_int64 x) with _ -> None
let of_int64 n = Z.of_int64 n

let to_int x = try Some (Z.to_int x) with _ -> None
let of_int n = Z.of_int n

let of_zint x = x
let to_zint x = x

let add x y = Z.add x y
let sub x y = Z.sub x y
let mul x y = Z.mul x y

let ediv x y =
  try
    let (q, r) = Z.ediv_rem x y in
    Some (q, r)
  with _ -> None

let add_n = add
let mul_n = mul
let ediv_n = ediv

let abs x = Z.abs x
let is_nat x =
  if Compare.Z.(x < Z.zero) then None else Some x
let neg x = Z.neg x
let int x = x

let shift_left x y =
  if Compare.Int.(Z.compare y (Z.of_int 256) > 0) then
    None
  else
    let y = Z.to_int y in
    Some (Z.shift_left x y)

let shift_right x y =
  if Compare.Int.(Z.compare y (Z.of_int 256) > 0) then
    None
  else
    let y = Z.to_int y in
    Some (Z.shift_right x y)

let shift_left_n = shift_left
let shift_right_n = shift_right

let logor x y = Z.logor x y
let logxor x y = Z.logxor x y
let logand x y = Z.logand x y
let lognot x = Z.lognot x