speedup

src/core/opamStd.ml

@@ -692,27 +692,27 @@ module OpamString = struct
   let rcut_at = cut_at_aux String.rindex
 
   let split s c =
-    let acc = ref [] in
-    let in_run = ref false in
-    let slice_start = ref 0 in
-    let len = String.length s in
-    for i=0 to len-1 do
-      if (String.get s i : char) = (c : char) then (
-        if not !in_run then (
-          if (i : int) > (!slice_start : int) then
-            acc := String.sub s !slice_start (i - !slice_start) :: !acc;
-          in_run := true;
-        )
-      ) else (
-        if !in_run then (
-          in_run := false;
-          slice_start := i;
-        )
-      )
-    done;
-    if not !in_run && (!slice_start : int) < (len : int) then
-      acc := String.sub s !slice_start (len - !slice_start) :: !acc;
-    List.rev !acc
+    let rec loop acc in_run slice_start len i s c =
+      if (i : int) < (len : int) then
+        if (String.get s i : char) = (c : char) then
+          if not in_run then
+            if (i : int) > (slice_start : int) then
+              loop (String.sub s slice_start (i - slice_start) :: acc)
+                true slice_start len (i + 1) s c
+            else
+              loop acc true slice_start len (i + 1) s c
+          else
+            loop acc in_run slice_start len (i + 1) s c
+        else if in_run then
+          loop acc false i len (i + 1) s c
+        else
+          loop acc in_run slice_start len (i + 1) s c
+      else if not in_run && (slice_start : int) < (len : int) then
+        String.sub s slice_start (len - slice_start) :: acc
+      else
+        acc
+    in
+    List.rev (loop [] false 0 (String.length s) 0 s c)
 
   let split_delim s c =
     let tokens = Re.(split_full (compile (char c)) s) in