(** Parameter Store entry codec.

    {v
    0x00  uint32  param_id
    0x04  uint16  len
    0x06  uint16  generation
    0x08  bytes   value (len bytes, padded to 4-byte alignment)
    0x??  uint32  crc32 (CRC-32C of param_id through value)
    v}

    The parameter store occupies blocks 1-16 of the virtio-blk device. Entries
    are appended sequentially. The guest reads the highest-generation entry for
    each param_id. *)

(** {1 Constants} *)

val max_value_len : int
(** Maximum value length: 240 bytes (248 - 8 header bytes). *)

(** {1 Type} *)

type t = {
  param_id : int;
  len : int;
  generation : int;
  value : string;
  crc32 : int;
}

val codec : t Wire.Codec.t
(** Wire codec for a parameter entry. The value is stored as a fixed 240-byte
    field (zero-padded). Total size: 252 bytes. *)

val v : param_id:int -> generation:int -> string -> t
(** [v ~param_id ~generation value] builds a parameter entry with computed CRC.
    Value is truncated to {!max_value_len}. *)

val value_bytes : t -> string
(** [value_bytes t] returns the meaningful value (first [len] bytes). *)

val check_crc : t -> bool
(** [check_crc t] validates the CRC-32C. *)

val pp : t Fmt.t
(** Pretty-print a parameter entry. *)

val equal : t -> t -> bool
(** Structural equality. *)