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Revert "Revert "Check fpr with 4 keys""

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This reverts commit 74c28b52c9.
This commit is contained in:
Martin Sumner 2017-10-24 15:22:12 +01:00
parent 74c28b52c9
commit f08faf6432
1 changed files with 13 additions and 16 deletions
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29
src/leveled_tinybloom.erl
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@ -50,8 +50,8 @@ check_hash(_Hash, <<>>) ->
false;
check_hash({_SegHash, Hash}, BloomBin) ->
SlotSplit = (byte_size(BloomBin) div ?BITS_PER_KEY) - 1,
{Slot, H0, H1} = split_hash(Hash, SlotSplit),
Mask = get_mask(H0, H1),
{Slot, H0, H1, H2, H3} = split_hash(Hash, SlotSplit),
Mask = get_mask(H0, H1, H2, H3),
Pos = Slot * ?BITS_PER_KEY,
IntSize = ?INTEGER_SIZE,
<<_H:Pos/binary, CheckInt:IntSize/integer, _T/binary>> = BloomBin,
@ -70,15 +70,12 @@ split_hash(Hash, SlotSplit) ->
Slot = Hash band SlotSplit,
H0 = (Hash bsr 4) band (?BAND_MASK),
H1 = (Hash bsr 10) band (?BAND_MASK),
{Slot, H0, H1}.
H2 = (Hash bsr 16) band (?BAND_MASK),
H3 = (Hash bsr 24) band (?BAND_MASK),
{Slot, H0, H1, H2, H3}.
get_mask(H0, H1) ->
case H0 == H1 of
true ->
1 bsl H0;
false ->
(1 bsl H0) + (1 bsl H1)
end.
get_mask(H0, H1, H2, H3) ->
(1 bsl H0) bor (1 bsl H1) bor (1 bsl H2) bor (1 bsl H3).
%% This looks ugly and clunky, but in tests it was quicker than modifying an
@ -88,8 +85,8 @@ add_hashlist([], _S, S0, S1) ->
IntSize = ?INTEGER_SIZE,
<<S0:IntSize/integer, S1:IntSize/integer>>;
add_hashlist([{_SegHash, TopHash}|T], SlotSplit, S0, S1) ->
{Slot, H0, H1} = split_hash(TopHash, SlotSplit),
Mask = get_mask(H0, H1),
{Slot, H0, H1, H2, H3} = split_hash(TopHash, SlotSplit),
Mask = get_mask(H0, H1, H2, H3),
case Slot of
0 ->
add_hashlist(T, SlotSplit, S0 bor Mask, S1);
@ -102,8 +99,8 @@ add_hashlist([], _S, S0, S1, S2, S3) ->
<<S0:IntSize/integer, S1:IntSize/integer,
S2:IntSize/integer, S3:IntSize/integer>>;
add_hashlist([{_SegHash, TopHash}|T], SlotSplit, S0, S1, S2, S3) ->
{Slot, H0, H1} = split_hash(TopHash, SlotSplit),
Mask = get_mask(H0, H1),
{Slot, H0, H1, H2, H3} = split_hash(TopHash, SlotSplit),
Mask = get_mask(H0, H1, H2, H3),
case Slot of
0 ->
add_hashlist(T, SlotSplit, S0 bor Mask, S1, S2, S3);
@ -130,8 +127,8 @@ add_hashlist([{_SegHash, TopHash}|T],
SlotSplit,
S0, S1, S2, S3, S4, S5, S6, S7, S8, S9,
SA, SB, SC, SD, SE, SF) ->
{Slot, H0, H1} = split_hash(TopHash, SlotSplit),
Mask = get_mask(H0, H1),
{Slot, H0, H1, H2, H3} = split_hash(TopHash, SlotSplit),
Mask = get_mask(H0, H1, H2, H3),
case Slot of
0 ->
add_hashlist(T,