[MirageOS-devel] [ANN] tjr_btree 0.1.0 (initial release)

[Tom Ridge <tom.j.ridge+list@xxxxxxxxxxxxxx>]

tjr_btree is a B-tree library written in OCaml. The examples include a simple on-disk key-value store.

https://github.com/tomjridge/tjr_btree

Example:

----

(** A simple example of a kv store. *)

open Small_string.O

(* SS is now an alias for Small_string *)

open Ss_ss_map_on_fd

(* filename *)

let fn = Default.default_filename

(* construct keys and values from an int *)

let k x = "k"^(string_of_int x) |> SS.of_string

let v x = "v"^(string_of_int x) |> SS.of_string

(* create and init store, write some values, and close *)

let do_write () = (

  print_endline "Writing...";

  (* create and initialize *)

  let s = ref (from_file ~fn ~create:true ~init:true) in

  (* get map operations *)

  let map_ops = imperative_map_ops s in

  (* write values *)

  for x=1 to 1000 do

    (* TODO this would be much faster if we used insert_many *)

    map_ops.insert (k x) (v x);

  done;

  (* close *)

  close !s

)

(* open store, delete some values, and close *)

let do_delete () = (

  print_endline "Deleting...";

  let s = ref (from_file ~fn ~create:false ~init:false) in

  let map_ops = imperative_map_ops s in

  for x=100 to 200 do

    map_ops.delete (k x);

  done;

  close !s

)

(* open store and check whether various keys and values are correct *)

let do_check () = (

  print_endline "Checking...";

  let s = ref (from_file ~fn ~create:false ~init:false) in

  let map_ops = imperative_map_ops s in

  assert(map_ops.find (SS.of_string("k100")) = None);

  assert(map_ops.find (SS.of_string("k1000")) = Some(SS.of_string("v1000")));

  close !s

)

(* actually execute the above *)

let _ = (

  do_write();

  do_delete();

  do_check()

)

----

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