package tezos-protocol-alpha

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package tezos-protocol-alpha
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A round represents an iteration of the single-shot consensus algorithm.

Rounds can be seen as an infinite, 0-indexed, list of durations. The durations are generated by an arithmetic progression depending on Constants_repr.minimal_block_delay (its initial value, a.k.a the one for round 0) and Constants_repr.delay_increment_per_round (its common difference) .

Round identifiers are non-negative 32 bit integers. This interface ensures that no negative round can be created.

type round
type t = round
val zero : t

Round zero

val succ : t -> t

Successor of the given round.

  • raises [Invalid_arg]

    if applied to the upper bound of the round integer representation.

val pred : t -> (t, Tezos_protocol_environment_alpha__Environment.Error_monad.error Tezos_protocol_environment_alpha__Environment.Error_monad.trace) result

Predecessor of the given round. Returns an error if applied to zero, as negative round are prohibited.

val of_int32 : int32 -> (t, Tezos_protocol_environment_alpha__Environment.Error_monad.error Tezos_protocol_environment_alpha__Environment.Error_monad.trace) result

Building a round from an int32. Returns an error if applied to a negative number.

val to_int32 : t -> int32
val of_int : int -> (t, Tezos_protocol_environment_alpha__Environment.Error_monad.error Tezos_protocol_environment_alpha__Environment.Error_monad.trace) result

Building a round from an int. Returns an error if applied to a negative number or a number greater than Int32.max_int.

val to_int : t -> (int, Tezos_protocol_environment_alpha__Environment.Error_monad.error Tezos_protocol_environment_alpha__Environment.Error_monad.trace) result

Building an int from a round. Returns an error if the value does not fit in max_int. (current 32bit encodings always fit in int on 64bit architecture though).

val to_slot : t -> committee_size:int -> (Slot_repr.t, Tezos_protocol_environment_alpha__Environment.Error_monad.error Tezos_protocol_environment_alpha__Environment.Error_monad.trace) result

Returns the slot corresponding to the given round r, that is r mod committee_size.

val encoding : t Data_encoding.t

Round encoding. Be aware that decoding a negative 32 bit integer would lead to an exception.

val pp : Format.formatter -> t -> unit
val (=) : t -> t -> bool
val (<>) : t -> t -> bool
val (<) : t -> t -> bool
val (<=) : t -> t -> bool
val (>=) : t -> t -> bool
val (>) : t -> t -> bool
val compare : t -> t -> int
val equal : t -> t -> bool
val max : t -> t -> t
val min : t -> t -> t
module Map : sig ... end

Round duration representation

module Durations : sig ... end
val level_offset_of_round : Durations.t -> round:t -> (Period_repr.t, Tezos_protocol_environment_alpha__Environment.Error_monad.error Tezos_protocol_environment_alpha__Environment.Error_monad.trace) result

level_offset_of_round round_durations ~round:r represents the offset of the starting time of round r with respect to the start of the level. round = 0 1 2 3 r

|-----|-----|-----|-----|-----|--- ... ... --|------|------- | <-------------------------------------------> level_offset

val timestamp_of_round : Durations.t -> predecessor_timestamp:Time_repr.t -> predecessor_round:t -> round:t -> (Time_repr.t, Tezos_protocol_environment_alpha__Environment.Error_monad.error Tezos_protocol_environment_alpha__Environment.Error_monad.trace) result

timestamp_of_round round_durations ~predecessor_timestamp:pred_ts ~predecessor_round:pred_round ~round returns the starting time of round round given that the timestamp and the round of the block at the previous level is pred_ts and pred_round, respectively.

pred_round = 0 pred_round

|-----|.. ... --|--------|-- ... --|------- | | | | pred_ts | | start_of_cur_level | | |-----|------|-- ... --|-------|- cur_round = 0 1 | round | res_ts

Precisely, the resulting timestamp is: pred_ts + round_duration(pred_round) + level_offset_of_round(round).

val timestamp_of_another_round_same_level : Durations.t -> current_timestamp:Time_repr.t -> current_round:t -> considered_round:t -> (Time_repr.t, Tezos_protocol_environment_alpha__Environment.Error_monad.error Tezos_protocol_environment_alpha__Environment.Error_monad.trace) result

timestamp_of_another_round_same_level round_durations ~current_timestamp ~current_round ~considered_round returns the starting time of round considered_round.

start of current level current ts result | | | | | | |-----|----...--|-- ... ------|- | | | | cur_round = 0 1 current considered round round

It also works when considered_round is lower than current_round.

Precisely, the resulting timestamp is: current_timestamp - level_offset_of_round(current_round) + level_offset_of_round(considered_round).

val round_of_timestamp : Durations.t -> predecessor_timestamp:Time_repr.t -> predecessor_round:t -> timestamp:Time_repr.t -> (t, Tezos_protocol_environment_alpha__Environment.Error_monad.error Tezos_protocol_environment_alpha__Environment.Error_monad.trace) result

round_of_timestamp round_durations ~predecessor_timestamp ~predecessor_round ~timestamp:ts returns the round to which the timestamp ts belongs to, given that the timestamp and the round of the block at the previous level is pred_ts and pred_round, respectively.

Precisely, the resulting round is: round_and_offset round_durations ~level_offset:diff where diff = ts - (predecessor_timestamp + round_duration(predecessor_round).

Returns an error when the timestamp is before the level start.

module Internals_for_test : sig ... end