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type t = {
  counter : Z.t;
      (** Each message is given a unique counter to allow for the batcher to
          receive multiple identical messages. *)
  content : string;  (** The actual content of the message. *)
}

let content_encoding =
  let open Data_encoding in
  def "sc_l2_message" ~description:"A hex encoded smart rollup message"
  @@ string' Hex

let encoding =
  let open Data_encoding in
  conv
    (fun {counter; content} -> (counter, content))
    (fun (counter, content) -> {counter; content})
  @@ obj2 (req "counter" z) (req "content" content_encoding)

let make =
  let counter = ref Z.zero in
  fun content ->
    let m = {content; counter = !counter} in
    counter := Z.succ !counter ;
    m

let content m = m.content

module Hash =
  Tezos_crypto.Blake2B.Make
    (Tezos_crypto.Base58)
    (struct
      let name = "sc_rollup_l2_message"

      let title = "A smart rollup layer 2 message"

      let b58check_prefix = "\003\250\179\247\196" (* scmsg(55) *)

      let size = None
    end)

let () =
  Tezos_crypto.Base58.check_encoded_prefix Hash.b58check_encoding "scmsg" 55

type hash = Hash.t

let hash t = Hash.hash_bytes [Data_encoding.Binary.to_bytes_exn encoding t]