[ocaml] fix formatting of values in pprz ocaml lib (#1135)

conf/messages.xml

@@ -11,7 +11,7 @@
 
    <message name="ALIVE" id="2">
      <description>alive/heartbeat message containing the MD5sum of the aircraft configuration</description>
-     <field name="md5sum" type="uint8[]"/>
+     <field name="md5sum" type="uint8[]" format="%x"/>
    </message>
 
    <message name="PONG" id="3">

sw/ground_segment/tmtc/messages.ml

@@ -83,7 +83,7 @@ let one_page = fun sender class_name (notebook:GPack.notebook) (topnote:GPack.no
                 sprintf "%s (%d)" literal_values.(i) i
               with _ ->
                 match format_ with
-                | Some f -> alt_value (Pprz.string_of_value_format f x)
+                | Some f -> alt_value (Pprz.formatted_string_of_value f x)
                 | _ -> alt_value (Pprz.string_of_value x)
           and display_value = fun () ->
             if notebook#page_num v#coerce = notebook#current_page then

sw/ground_segment/tmtc/server.ml

@@ -311,11 +311,11 @@ let send_telemetry_status = fun a ->
     [ "ac_id", Pprz.String id;
       "link_id", Pprz.String link_id;
       "time_since_last_msg", Pprz.Float (U.gettimeofday () -. a.last_msg_date); (* don't use rx_lost_time from LINK_REPORT so it also works in simulation *)
-      "rx_bytes", Pprz.Int link_status.rx_bytes;
-      "rx_msgs", Pprz.Int link_status.rx_msgs;
+      "rx_bytes", Pprz.Int32 (Int32.of_int link_status.rx_bytes);
+      "rx_msgs", Pprz.Int32 (Int32.of_int link_status.rx_msgs);
       "rx_bytes_rate", Pprz.Float link_status.rx_bytes_rate;
-      "tx_msgs", Pprz.Int link_status.tx_msgs;
-      "uplink_lost_time", Pprz.Int datalink_status.uplink_lost_time;
+      "tx_msgs", Pprz.Int32 (Int32.of_int link_status.tx_msgs);
+      "uplink_lost_time", Pprz.Int32 (Int32.of_int datalink_status.uplink_lost_time);
       "uplink_msgs", Pprz.Int datalink_status.uplink_msgs;
       "downlink_msgs", Pprz.Int datalink_status.downlink_msgs;
       "downlink_rate", Pprz.Int datalink_status.downlink_rate;
@@ -401,8 +401,8 @@ let send_aircraft_msg = fun ac ->
             let values = ["ac_id", Pprz.String ac;
                           "cur_block", Pprz.Int a.cur_block;
                           "cur_stage", Pprz.Int a.cur_stage;
-                          "stage_time", Pprz.Int a.stage_time;
-                          "block_time", Pprz.Int a.block_time;
+                          "stage_time", Pprz.Int32 (Int32.of_int a.stage_time);
+                          "block_time", Pprz.Int32 (Int32.of_int a.block_time);
                           "target_lat", f ((Rad>>Deg)a.desired_pos.posn_lat);
                           "target_long", f ((Rad>>Deg)a.desired_pos.posn_long);
                           "target_alt", Pprz.Float a.desired_altitude;
@@ -432,7 +432,7 @@ let send_aircraft_msg = fun ac ->
     let state_filter_mode = get_indexed_value state_filter_modes a.state_filter_mode
     and kill_mode = if a.kill_mode then "ON" else "OFF" in
     let values = ["ac_id", Pprz.String ac;
-                  "flight_time", Pprz.Int a.flight_time;
+                  "flight_time", Pprz.Int32 (Int32.of_int a.flight_time);
                   "ap_mode", Pprz.String ap_mode;
                   "gaz_mode", Pprz.String gaz_mode;
                   "lat_mode", Pprz.String lat_mode;

sw/lib/ocaml/pprz.ml

@@ -169,26 +169,15 @@ let rec string_of_value = function
       | _ -> String.concat separator l
 
 
-let magic = fun x -> (Obj.magic x:('a,'b,'c) Pervasives.format)
-
-(* FIXME temporary solution, the complete formatted_string_of_value function
-   causes a segfault in server and GCS
-   magic format also cases segfaults with OCaml 4.02, so complety disable this for now
-*)
-let string_of_value_format = fun format v ->
-  match v with
-    (*Float x -> sprintf (magic format) x*)
-  | v -> string_of_value v
-
-(* FIXME: causes a segfault in server and GCS. *)
 let rec formatted_string_of_value = fun format v ->
+  let f = fun x -> Scanf.format_from_string format x in
   match v with
-    | Int x -> sprintf (magic format) x
-    | Float x -> sprintf (magic format) x
-    | Int32 x -> sprintf (magic format) x
-    | Int64 x -> sprintf (magic format) x
-    | Char x -> sprintf (magic format) x
-    | String x -> sprintf (magic format) x
+    | Int x -> sprintf (f "%d") x
+    | Float x -> sprintf (f "%f") x
+    | Int32 x -> sprintf (f "%ld") x
+    | Int64 x -> sprintf (f "%Ld") x
+    | Char x -> sprintf (f "%c") x
+    | String x ->sprintf "%s" x
     | Array a ->
         let l = (Array.to_list (Array.map (formatted_string_of_value format) a)) in
         match a.(0) with
@@ -736,9 +725,7 @@ module MessagesOfXml(Class:CLASS_Xml) = struct
          try List.assoc field_name values with
              Not_found ->
                default_value field._type in
-       (* should actually use this here, but it segfaults, so disable format strings for now
-       formatted_string_of_value field.fformat v)*)
-       string_of_value_format field.fformat v)
+       formatted_string_of_value field.fformat v)
      msg.fields)
 
   let message_send = fun ?timestamp ?link_id sender msg_name values ->

sw/lib/ocaml/pprz.mli

@@ -63,8 +63,7 @@ val is_fixed_array_type : string -> bool
 
 val size_of_field : field -> int
 val string_of_value : value -> string
-val formatted_string_of_value : 'a -> value -> string
-val string_of_value_format : 'a -> value -> string
+val formatted_string_of_value : format -> value -> string
 val int_of_value : value -> int (* May raise Invalid_argument *)
 type type_descr = {
     format : string ;