refactor(jid): add pos information to uchars type

1 files changed, 24 insertions, 21 deletions

diff --git a/lib/jid.ml b/lib/jid.ml
index 9d9bb58..47de37d 100644
--- a/lib/jid.ml
+++ b/lib/jid.ml
@@ -6,7 +6,7 @@ type t = {
 
 exception InvalidUTF8
 
-type uchars = Uchar.t list
+type uchars = (Uchar.t * int) list
 
 let uchars_of_string s : uchars =
   let open Uchar in
@@ -21,33 +21,36 @@ let uchars_of_string s : uchars =
       else
         let k = utf_decode_length c in
         let u = utf_decode_uchar c in
-        loop (u :: acc) (i + k)
+        loop ((u, i) :: acc) (i + k)
   in loop [] 0
 
-let of_string (s : string) : t =
+let of_string (jid : string) : t =
   let open List in
-  let jid = uchars_of_string s in
-  let rest, resourcepart =
-    find_mapi (fun i c ->
+  let open String in
+  let u_jid = uchars_of_string jid in
+  let u_barejid, domain_end =
+    find_mapi (fun u_i (c, i) ->
         if c = Uchar.of_char '/'
-        then Some (take i jid, drop (i+1) jid |> string_of_uchars)
-        else None) jid
-    |> Option.fold ~none:(jid, None) ~some:(fun (rest, res) -> rest, Some res)
+        then Some (u_i, i)
+        else None) u_jid
+    |> Option.fold ~none:(u_jid, None) ~some:(fun (u_i, i) -> take u_i u_jid, Some i)
   in
-  let localpart, domainpart =
-    rev rest
-    |> find_mapi (fun i c ->
+  let domain_begin =
+    rev u_barejid
+    |> find_map (fun (c, i) ->
            if c = Uchar.of_char '@'
-           then let idx = length rest - i
-                in Some (take (idx-1) rest |> string_of_uchars,
-                         drop idx rest |> string_of_uchars)
+           then Some (i+1)
            else None)
-    |> Option.fold ~none:(None, rest |> string_of_uchars) ~some:(fun (loc, dom) -> Some loc, dom)
-  in {
-       localpart;
-       resourcepart;
-       domainpart;
-     }
+  in
+  let open Option in {
+      localpart = map (fun i -> sub jid 0 (i - 1)) domain_begin;
+      domainpart =
+        begin
+          let b = (value ~default:0 domain_begin) in
+          sub jid b ((value ~default:(length jid) domain_end) - b)
+        end;
+      resourcepart = map (fun i -> sub jid (i + 1) (length jid - i - 1)) domain_end;
+    }
 
 let%expect_test {|A "bare JID"|} =
   "juliet@example.com" |> of_string |> show |> print_string;