unikernel/duniverse/ocaml-re/lib/mark_infos.ml

@@ -0,0 +1,55 @@
+open Import
+
+type t = int array
+
+let make marks =
+  let len = 1 + List.fold_left ~f:(fun ma (i, _) -> max ma i) ~init:(-1) marks in
+  let t = Array.make len (-1) in
+  let set (i, v) = t.(i) <- v in
+  List.iter ~f:set marks;
+  t
+;;
+
+let test t i = if 2 * i >= Array.length t then false else t.(2 * i) <> -1
+
+module Offset = struct
+  type t = int
+
+  let is_present t = t >= 0
+  let get_no_check t = t
+end
+
+let start_offset t i =
+  let start_i = 2 * i in
+  if start_i + 1 >= Array.length t then -1 else t.(start_i)
+;;
+
+let stop_offset t i =
+  let stop_i = (2 * i) + 1 in
+  if stop_i >= Array.length t then -1 else t.(stop_i)
+;;
+
+let offset t i =
+  let start_i = 2 * i in
+  let stop_i = start_i + 1 in
+  if stop_i >= Array.length t
+  then None
+  else (
+    let start = t.(start_i) in
+    if start = -1
+    then None
+    else (
+      let stop = t.(stop_i) in
+      Some (start, stop)))
+;;
+
+let iteri t ~f =
+  for i = 0 to (Array.length t / 2) - 1 do
+    let idx = 2 * i in
+    let start = t.(idx) in
+    if start <> -1
+    then (
+      let stop = t.(idx + 1) in
+      f i start stop)
+  done
+;;