(** Core types for Lithos *)

type ro

type rw

type page_id = int64

type metadata =
  { version : int
  ; page_size : int
  ; root_bucket : page_id option
  }

type txn_state =
  | Active
  | Committed
  | Rolled_back

type key = bytes

type value = (char, Bigarray.int8_unsigned_elt, Bigarray.c_layout) Bigarray.Array1.t

let key_of_string s = Bytes.of_string s

let string_of_key k = Bytes.to_string k

let value_of_bytes b =
  let len = Bytes.length b in
  let arr = Bigarray.Array1.create Bigarray.char Bigarray.c_layout len in
  for i = 0 to len - 1 do
    Bigarray.Array1.set arr i (Bytes.get b i)
  done;
  arr
;;

let bytes_of_value v =
  let len = Bigarray.Array1.dim v in
  let b = Bytes.create len in
  for i = 0 to len - 1 do
    Bytes.set b i (Bigarray.Array1.get v i)
  done;
  b
;;

let value_of_string s = value_of_bytes (Bytes.of_string s)

let string_of_value v = Bytes.to_string (bytes_of_value v)