Keep trees empty on merge

Done't blow out a tree unnecessarily on merge
2017-09-29 15:28:17 +01:00 · 2017-09-29 15:28:17 +01:00 · fd4fbf7ea8
commit fd4fbf7ea8
parent 5e6534fb49
1 changed files with 8 additions and 1 deletions
--- a/src/leveled_tictac.erl
+++ b/src/leveled_tictac.erl
@ -278,7 +278,14 @@ merge_trees(TreeA, TreeB) ->
        fun(SQN, MergeL2) ->
            L2A = get_level2(TreeA, SQN),
            L2B = get_level2(TreeB, SQN),
-            NewLevel2 = merge_binaries(L2A, L2B),
+            BothEmpty = (L2A == ?EMPTY) and (L2B == ?EMPTY),
+            NewLevel2 = 
+                case BothEmpty of
+                    true ->
+                        ?EMPTY;
+                    false ->
+                        merge_binaries(L2A, L2B)
+                end,
            array:set(SQN, NewLevel2, MergeL2)
        end,
    NewLevel2 = lists:foldl(MergeFun,