Change collate_fun contract from true|false to -1, 0, 1

1 files changed, 40 insertions, 31 deletions

diff --git a/src/ebtree/src/ebtree.erl b/src/ebtree/src/ebtree.erl
index f08e1e9be..b227be035 100644
--- a/src/ebtree/src/ebtree.erl
+++ b/src/ebtree/src/ebtree.erl
@@ -881,36 +881,34 @@ in_range(#tree{} = Tree, StartOfRange, Key, EndOfRange) ->
 
 
 greater_than(#tree{} = Tree, A, B) ->
-    not less_than_or_equal(Tree, A, B).
+    collate(Tree, A, B) == 1.
 
 
-greater_than_or_equal(#tree{} = _Tree, A, A) ->
-    true;
-
 greater_than_or_equal(#tree{} = Tree, A, B) ->
-    greater_than(Tree, A, B).
-
+    collate(Tree, A, B) > -1.
 
-less_than(#tree{} = _Tree, A, A) ->
-    false;
 
 less_than(#tree{} = Tree, A, B) ->
-    less_than_or_equal(Tree, A, B).
+    collate(Tree, A, B) == -1.
+
 
+less_than_or_equal(#tree{} = Tree, A, B) ->
+    collate(Tree, A, B) < 1.
 
-less_than_or_equal(#tree{} = _Tree, ?MIN, _B) ->
-    true;
 
-less_than_or_equal(#tree{} = _Tree, _A, ?MIN) ->
-    false;
+collate(#tree{} = _Tree, ?MIN, _B) ->
+    -1;
 
-less_than_or_equal(#tree{} = _Tree, ?MAX, _B) ->
-    false;
+collate(#tree{} = _Tree, _A, ?MIN) ->
+    1;
 
-less_than_or_equal(#tree{} = _Tree, _A, ?MAX) ->
-    true;
+collate(#tree{} = _Tree, ?MAX, _B) ->
+    1;
 
-less_than_or_equal(#tree{} = Tree, A, B) ->
+collate(#tree{} = _Tree, _A, ?MAX) ->
+    -1;
+
+collate(#tree{} = Tree, A, B) ->
     #tree{collate_fun = CollateFun} = Tree,
     CollateFun(A, B).
 
@@ -919,23 +917,27 @@ umerge_members(#tree{} = Tree, List1, List2) ->
     #tree{collate_fun = CollateFun} = Tree,
     CollateWrapper = fun
         ({K1, _V1}, {K2, _V2}) ->
-            CollateFun(K1, K2);
+            CollateFun(K1, K2) < 1;
         ({_F1, L1, _V1, _R1}, {_F2, L2, _V2, _R2}) ->
-            CollateFun(L1, L2)
+            CollateFun(L1, L2) < 1
     end,
     lists:umerge(CollateWrapper, List1, List2).
 
 
 sort_keys(#tree{} = Tree, List) ->
     #tree{collate_fun = CollateFun} = Tree,
-    lists:sort(CollateFun, List).
+    CollateWrapper = fun
+        (K1, K2) ->
+            CollateFun(K1, K2) < 1
+    end,
+    lists:sort(CollateWrapper, List).
 
 
 sort_nodes(#tree{} = Tree, List) ->
     #tree{collate_fun = CollateFun} = Tree,
     CollateWrapper = fun
         (#node{} = N1, #node{} = N2) ->
-            CollateFun(first_key(N1), first_key(N2))
+            CollateFun(first_key(N1), first_key(N2)) < 1
     end,
     lists:sort(CollateWrapper, List).
 
@@ -944,9 +946,9 @@ sort_members(#tree{} = Tree, List) ->
     #tree{collate_fun = CollateFun} = Tree,
     CollateWrapper = fun
         ({K1, _V1}, {K2, _V2}) ->
-            CollateFun(K1, K2);
+            CollateFun(K1, K2) < 1;
         ({_F1, L1, _V1, _R1}, {_F2, L2, _V2, _R2}) ->
-            CollateFun(L1, L2)
+            CollateFun(L1, L2) < 1
     end,
     lists:sort(CollateWrapper, List).
 
@@ -955,15 +957,22 @@ usort_members(#tree{} = Tree, List) ->
     #tree{collate_fun = CollateFun} = Tree,
     CollateWrapper = fun
         ({K1, _V1}, {K2, _V2}) ->
-            CollateFun(K1, K2);
+            CollateFun(K1, K2) < 1;
         ({_F1, L1, _V1, _R1}, {_F2, L2, _V2, _R2}) ->
-            CollateFun(L1, L2)
+            CollateFun(L1, L2) < 1
     end,
     lists:usort(CollateWrapper, List).
 
 
-collate_raw(K1, K2) ->
-    K1 =< K2.
+collate_raw(K1, K2) when K1 < K2 ->
+    -1;
+
+collate_raw(K1, K2) when K1 > K2 ->
+    1;
+
+collate_raw(K, K) ->
+    0.
+
 
 %% encoding function
 
@@ -1235,7 +1244,7 @@ raw_collation_test() ->
 
 custom_collation_test() ->
     Db = erlfdb_util:get_test_db([empty]),
-    CollateFun = fun(A, B) -> B =< A end,
+    CollateFun = fun(A, B) -> collate_raw(B, A) end,
     Tree = open(Db, <<1,2,3>>, 4, [{collate_fun, CollateFun}]),
     insert(Db, Tree, 1, 1),
     insert(Db, Tree, 2, 2),
@@ -1299,7 +1308,7 @@ custom_collation_range_test_() ->
         Db = erlfdb_util:get_test_db([empty]),
         Max = 1000,
         Keys = [X || {_, X} <- lists:sort([ {rand:uniform(), N} || N <- lists:seq(1, Max)])],
-        CollateFun = fun(A, B) -> B =< A end,
+        CollateFun = fun(A, B) -> collate_raw(B, A) end,
         Tree = open(Db, <<1,2,3>>, 10, [{collate_fun, CollateFun}]),
         lists:foldl(fun(Key, T) -> insert(Db, T, Key, Key + 1) end, Tree, Keys),
         lists:foreach(
@@ -1323,7 +1332,7 @@ custom_collation_reverse_range_test_() ->
         Db = erlfdb_util:get_test_db([empty]),
         Max = 1000,
         Keys = [X || {_, X} <- lists:sort([ {rand:uniform(), N} || N <- lists:seq(1, Max)])],
-        CollateFun = fun(A, B) -> B =< A end,
+        CollateFun = fun(A, B) -> collate_raw(B, A) end,
         Tree = open(Db, <<1,2,3>>, 10, [{collate_fun, CollateFun}]),
         lists:foldl(fun(Key, T) -> insert(Db, T, Key, Key + 1) end, Tree, Keys),
         lists:foreach(