Better implementation.

src/metadataID3v2.ml

@@ -147,41 +147,35 @@ let parse ?recode f : metadata =
           raise Exit);
         let tag = R.read_tag ~label:id ~length:size f in
         len := !len - (size + 10);
-        match tag with
-          | None -> ()
-          | Some data ->
-              let len = String.length data in
-              if List.mem id ["SEEK"] then ()
-              else if id = "TXXX" then (
-                let encoding = int_of_char data.[0] in
-                let data = String.sub data 1 (len - 1) in
-                let recode = recode encoding in
-                let id, data =
-                  let n = next_substring encoding data in
-                  ( String.sub data 0 n,
-                    String.sub data n (String.length data - n) )
-                in
-                let id = recode id in
-                let data = recode data in
-                tags := (id, data) :: !tags)
-              else if id = "COMM" then (
-                let encoding = int_of_char data.[0] in
-                let recode = recode encoding in
-                let data = String.sub data 1 (len - 1) in
-                (* We ignore the language description of the comment. *)
-                let n =
-                  try next_substring encoding data with Not_found -> 0
-                in
-                let data =
-                  String.sub data n (String.length data - n) |> recode
-                in
-                tags := ("comment", data) :: !tags)
-              else if id.[0] = 'T' then (
-                let encoding = int_of_char data.[0] in
-                let recode = recode encoding in
-                let data = String.sub data 1 (len - 1) |> recode in
-                tags := (normalize_id id, data) :: !tags)
-              else tags := (normalize_id id, data) :: !tags)
+        if tag = None then raise Exit;
+        let data = Option.get tag in
+        let len = String.length data in
+        if List.mem id ["SEEK"] then ()
+        else if id = "TXXX" then (
+          let encoding = int_of_char data.[0] in
+          let data = String.sub data 1 (len - 1) in
+          let recode = recode encoding in
+          let id, data =
+            let n = next_substring encoding data in
+            (String.sub data 0 n, String.sub data n (String.length data - n))
+          in
+          let id = recode id in
+          let data = recode data in
+          tags := (id, data) :: !tags)
+        else if id = "COMM" then (
+          let encoding = int_of_char data.[0] in
+          let recode = recode encoding in
+          let data = String.sub data 1 (len - 1) in
+          (* We ignore the language description of the comment. *)
+          let n = try next_substring encoding data with Not_found -> 0 in
+          let data = String.sub data n (String.length data - n) |> recode in
+          tags := ("comment", data) :: !tags)
+        else if id.[0] = 'T' then (
+          let encoding = int_of_char data.[0] in
+          let recode = recode encoding in
+          let data = String.sub data 1 (len - 1) |> recode in
+          tags := (normalize_id id, data) :: !tags)
+        else tags := (normalize_id id, data) :: !tags)
     with Exit -> ()
   done;
   List.rev !tags