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Add simple merge

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Allow for tictac trees to be merged
This commit is contained in:
martinsumner 2017-06-15 16:16:19 +01:00
parent 86b11803c9
commit 959e7f932f
1 changed files with 52 additions and 1 deletions
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53
src/leveled_tictac.erl
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@ -68,7 +68,7 @@
-define(SEGMENT_COUNT, ?LEVEL1_WIDTH * ?LEVEL2_WIDTH).
-define(HASH_SIZE, 4).
-record(tictactree, {treeID ::integer(),
-record(tictactree, {treeID :: any(),
level1 :: binary(),
level2 :: array:array()}).
@ -143,6 +143,25 @@ find_dirtyleaves(SrcTree, SinkTree) ->
lists:sort(lists:foldl(FoldFun, [], IdxList)).
merge_trees(TreeA, TreeB) ->
MergedTree = new_tree(merge),
L1A = TreeA#tictactree.level1,
L1B = TreeB#tictactree.level1,
NewLevel1 = merge_binaries(L1A, L1B),
MergeFun =
fun(SQN, MergeL2) ->
L2A = array:get(SQN, TreeA#tictactree.level2),
L2B = array:get(SQN, TreeA#tictactree.level2),
NewLevel2 = merge_binaries(L2A, L2B),
array:set(SQN, NewLevel2, MergeL2)
end,
NewLevel2 = lists:foldl(MergeFun,
MergedTree#tictactree.level2,
lists:seq(0, ?LEVEL1_WIDTH - 1)),
MergedTree#tictactree{level1 = NewLevel1, level2 = NewLevel2}.
%%%============================================================================
%%% Internal functions
@ -166,6 +185,13 @@ segmentcompare(SrcBin, SnkBin, Acc, Counter) ->
get_segment(Key) ->
erlang:phash2(Key) band (?SEGMENT_COUNT - 1).
merge_binaries(BinA, BinB) ->
BitSize = bit_size(BinA),
BitSize = bit_size(BinB),
<<AInt:BitSize/integer>> = BinA,
<<BInt:BitSize/integer>> = BinB,
MergedInt = AInt bxor BInt,
<<MergedInt:BitSize/integer>>.
%%%============================================================================
%%% Test
@ -205,6 +231,31 @@ simple_test() ->
?assertMatch(true, lists:member(get_segment("K3"), DL1)),
?assertMatch(false, lists:member(get_segment("K1"), DL1)).
merge_test() ->
HashFun = fun(_K, V) -> erlang:phash2(V) end,
TreeX0 = new_tree(0),
TreeX1 = add_kv(TreeX0, "X1", 1, HashFun),
TreeX2 = add_kv(TreeX1, "X2", 2, HashFun),
TreeX3 = add_kv(TreeX2, "X3", 3, HashFun),
TreeX4 = add_kv(TreeX3, "X3", 4, HashFun),
TreeY0 = new_tree(0),
TreeY1 = add_kv(TreeY0, "Y1", 101, HashFun),
TreeY2 = add_kv(TreeY1, "Y2", 102, HashFun),
TreeY3 = add_kv(TreeY2, "Y3", 103, HashFun),
TreeY4 = add_kv(TreeY3, "Y3", 104, HashFun),
TreeZ1 = add_kv(TreeX4, "Y1", 101, HashFun),
TreeZ2 = add_kv(TreeZ1, "Y2", 102, HashFun),
TreeZ3 = add_kv(TreeZ2, "Y3", 103, HashFun),
TreeZ4 = add_kv(TreeZ3, "Y3", 104, HashFun),
TreeM0 = merge_trees(TreeX4, TreeY4),
?assertMatch(true, TreeM0#tictactree.level1 == TreeZ4#tictactree.level1),
TreeM1 = merge_trees(TreeX3, TreeY4),
?assertMatch(false, TreeM1#tictactree.level1 == TreeZ4#tictactree.level1).
-endif.