Source file sc_rollup_costs.ml

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module S = Saturation_repr

module Constants = struct
  (* equal to Michelson_v1_gas.Cost_of.Unparsing.contract_optimized *)
  let cost_decoding_contract_optimized = S.safe_int 70

  (* equal to Michelson_v1_gas.Cost_of.Unparsing.key_hash_optimized *)
  let cost_decoding_key_hash_optimized = S.safe_int 70

  (* Set to the cost of encoding a pkh defined in {!Michelson_v1_gas} divided
     by the number of characters of a pkh, with the result rounded up, i.e.
     70/20 + 1.
     To be updated when benchmarking is completed. *)
  let cost_encode_string_per_byte = S.safe_int 4

  (* Cost of serializing a state hash. *)
  let cost_serialize_state_hash =
    let len = S.safe_int State_hash.size in
    S.Syntax.(cost_encode_string_per_byte * len)

  (* Cost of serializing a commitment hash. *)
  let cost_serialize_commitment_hash =
    let len = S.safe_int Sc_rollup_commitment_repr.Hash.size in
    S.Syntax.(cost_encode_string_per_byte * len)

  (* Cost of serializing a commitment. The cost of serializing the level and
     number of ticks (both int32) is negligible. *)
  let cost_serialize_commitment =
    S.Syntax.(cost_serialize_state_hash + cost_serialize_commitment_hash)

  (* Cost of serializing an operation hash. *)
  let cost_serialize_operation_hash =
    let len = S.safe_int Operation_hash.size in
    S.Syntax.(cost_encode_string_per_byte * len)

  (* Cost of serializing a nonce. The cost of serializing the index (an int32)
     is negligible. *)
  let cost_serialize_nonce = cost_serialize_operation_hash
end

(* Reusing model from {!Ticket_costs.has_tickets_of_ty_cost}. *)
let is_valid_parameters_ty_cost ~ty_size =
  let fixed_cost = S.safe_int 10 in
  let coeff = S.safe_int 6 in
  S.add fixed_cost (S.mul coeff ty_size)

let cost_serialize_internal_inbox_message
    (internal_inbox_message :
      Sc_rollup_inbox_message_repr.internal_inbox_message) =
  match internal_inbox_message with
  | Transfer {payload; sender = _; source = _; destination = _} ->
      let lexpr = Script_repr.lazy_expr payload in
      let expr_cost = Script_repr.force_bytes_cost lexpr in
      S.Syntax.(
        expr_cost + Constants.cost_decoding_contract_optimized
        + Constants.cost_decoding_key_hash_optimized)
  | Start_of_level -> Saturation_repr.zero
  | End_of_level -> Saturation_repr.zero
  | Protocol_migration _ -> Saturation_repr.zero
  | Info_per_level _ -> Saturation_repr.zero

(* Derived from benchmark in
   [Sc_rollup_benchmarks.Sc_rollup_deserialize_output_proof_benchmark] and model
   [model_Sc_rollup_deserialize_output_proof_benchmark]. *)
(* fun size -> (7086.16259141 + (6.04996016914 * size)) *)
let cost_deserialize_output_proof ~bytes_len =
  let open S.Syntax in
  let v0 = S.safe_int bytes_len in
  S.safe_int 7100 + ((v0 lsl 2) + (v0 lsl 1))

let cost_serialize_external_inbox_message ~bytes_len =
  let len = S.safe_int bytes_len in
  S.Syntax.(Constants.cost_encode_string_per_byte * len)

(* Equal to Michelson_v1_gas.Cost_of.Interpreter.blake2b. *)
let cost_hash_bytes ~bytes_len =
  let open S.Syntax in
  let v0 = S.safe_int bytes_len in
  S.safe_int 430 + v0 + (v0 lsr 3)

let cost_compare a_size_in_bytes b_size_in_bytes =
  let open S.Syntax in
  let size_in_bytes = Compare.Int.min a_size_in_bytes b_size_in_bytes in
  let v0 = S.safe_int size_in_bytes in
  S.safe_int 35 + ((v0 lsr 6) + (v0 lsr 7))

let cost_search_in_tick_list len tick_size =
  let open S.Syntax in
  S.safe_int len * cost_compare tick_size tick_size

let cost_check_dissection ~number_of_states ~tick_size ~hash_size =
  let open S.Syntax in
  cost_search_in_tick_list number_of_states tick_size
  + (S.safe_int 2 * cost_compare hash_size hash_size)

let cost_add_message ~current_index ~msg_len =
  let open S.Syntax in
  let hash_cell_cost =
    Skip_list_costs.model_hash_cell_computed_backpointers_count
      ~index:current_index
  in
  let hash_content_cost = cost_hash_bytes ~bytes_len:msg_len in
  let next_cell_cost =
    Skip_list_costs.model_next ~length:(Z.succ current_index)
  in
  hash_cell_cost + hash_content_cost + next_cell_cost

(* Derived from benchmark in
   [Sc_rollup_benchmarks.Sc_rollup_verify_output_proof_benchmark] and model
   [model_Sc_rollup_verify_output_proof_benchmark] with estimated parameters:
   [fun size -> (103413.141163 + (6.85566158429 * size))] *)
let cost_verify_output_proof ~bytes_len =
  let open S.Syntax in
  let size = S.safe_int bytes_len in
  let v0 = size in
  S.safe_int 103450 + (v0 lsl 2) + (v0 lsl 1) + v0