Source file zplus.ml

(*****************************************************************************)
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(* Open Source License                                                       *)
(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com>     *)
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(* let re_trailing_null =
   Re_pcre.regexp "^(.*?)\000*$"

   let remove_trailing_null s =
   Re.get (Re.exec re_trailing_null s) 1 *)

let remove_trailing_null s =
  let n = String.length s in
  let i = ref (n - 1) in
  while !i >= 0 && s.[!i] = '\000' do
    i := !i - 1
  done ;
  String.sub s 0 (!i + 1)

let serialize z =
  let n = if Z.(lt z zero) then Z.(neg (add (add z z) one)) else Z.(add z z) in
  n |> Z.to_bits |> remove_trailing_null

let deserialize z =
  let n = Z.of_bits z in
  let z = Z.shift_right_trunc n 1 in
  if Z.(n land one = zero) then z else Z.neg z

let leq a b = Z.compare a b <= 0

let geq a b = Z.compare a b >= 0

let lt a b = Z.compare a b < 0

let gt a b = Z.compare a b > 0

let ( < ) = lt

let ( > ) = gt

let ( <= ) = leq

let ( >= ) = geq

let zero = Z.zero

let one = Z.one

let invert a n = try Some (Z.invert a n) with Division_by_zero -> None