Martin Sumner
parent
3fd5260cd9
commit
29a2d9fc35
2 changed files with 96 additions and 44 deletions
|
|
@ -83,12 +83,12 @@
|
|||
|
||||
-spec segment_hash(any()) -> {integer(), integer()}.
|
||||
%% @doc
|
||||
%% Return two integers - the segment ID and a second integer for spare
|
||||
%% Return two 16 bit integers - the segment ID and a second integer for spare
|
||||
%% entropy. The hashed should be used in blooms or indexes such that some
|
||||
%% speed can be gained if just the segment ID is known - but more can be
|
||||
%% gained should the extended hash (with the second element) is known
|
||||
segment_hash(Key) when is_binary(Key) ->
|
||||
<<SegmentID:16/integer, ExtraHash:32/integer, _Rest/binary>> =
|
||||
<<SegmentID:16/integer, ExtraHash:16/integer, _Rest/binary>> =
|
||||
crypto:hash(md5, Key),
|
||||
{SegmentID, ExtraHash};
|
||||
segment_hash(Key) ->
|
||||
|
|
|
|||
|
|
@ -16,12 +16,9 @@
|
|||
check_hash/2
|
||||
]).
|
||||
|
||||
-define(BLOOM_SIZE_BITS, 128).
|
||||
% Size of each bloom in bits
|
||||
% If hash space is now split into 8 different blooms of this size there
|
||||
% will be 8 bits per key.
|
||||
-define(BLOOM_SIZE_BYTES, 16). % Bits divided by 8
|
||||
-define(BAND_MASK, ?BLOOM_SIZE_BITS - 1).
|
||||
-define(BITS_PER_KEY, 8). % Must be 8 or 4
|
||||
-define(INTEGER_SIZE, ?BITS_PER_KEY * 8).
|
||||
-define(BAND_MASK, ?INTEGER_SIZE - 1).
|
||||
|
||||
|
||||
%%%============================================================================
|
||||
|
|
@ -37,8 +34,9 @@ create_bloom(HashList) ->
|
|||
<<>>;
|
||||
L when L > 32 ->
|
||||
add_hashlist(HashList,
|
||||
7,
|
||||
0, 0, 0, 0, 0, 0, 0, 0);
|
||||
15,
|
||||
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
||||
0, 0, 0, 0, 0, 0);
|
||||
L when L > 16 ->
|
||||
add_hashlist(HashList, 3, 0, 0, 0, 0);
|
||||
_ ->
|
||||
|
|
@ -51,12 +49,11 @@ create_bloom(HashList) ->
|
|||
check_hash(_Hash, <<>>) ->
|
||||
false;
|
||||
check_hash({_SegHash, Hash}, BloomBin) ->
|
||||
SlotSplit = (byte_size(BloomBin) div ?BLOOM_SIZE_BYTES) - 1,
|
||||
{Slot, H0, H1, H2, H3} = split_hash(Hash, SlotSplit),
|
||||
Mask = get_mask(H0, H1, H2, H3),
|
||||
IntSize = ?BLOOM_SIZE_BITS,
|
||||
Pos = Slot * ?BLOOM_SIZE_BYTES,
|
||||
io:format("Pos ~w SlotSplit ~w BloomSize ~w~n", [Pos, SlotSplit, byte_size(BloomBin)]),
|
||||
SlotSplit = (byte_size(BloomBin) div ?BITS_PER_KEY) - 1,
|
||||
{Slot, H0, H1} = split_hash(Hash, SlotSplit),
|
||||
Mask = get_mask(H0, H1),
|
||||
Pos = Slot * ?BITS_PER_KEY,
|
||||
IntSize = ?INTEGER_SIZE,
|
||||
<<_H:Pos/binary, CheckInt:IntSize/integer, _T/binary>> = BloomBin,
|
||||
case CheckInt band Mask of
|
||||
Mask ->
|
||||
|
|
@ -72,26 +69,27 @@ check_hash({_SegHash, Hash}, BloomBin) ->
|
|||
split_hash(Hash, SlotSplit) ->
|
||||
Slot = Hash band SlotSplit,
|
||||
H0 = (Hash bsr 4) band (?BAND_MASK),
|
||||
H1 = (Hash bsr 11) band (?BAND_MASK),
|
||||
H2 = (Hash bsr 18) band (?BAND_MASK),
|
||||
H3 = (Hash bsr 25) band (?BAND_MASK),
|
||||
{Slot, H0, H1, H2, H3}.
|
||||
H1 = (Hash bsr 10) band (?BAND_MASK),
|
||||
{Slot, H0, H1}.
|
||||
|
||||
get_mask(H0, H1, H2, H3) ->
|
||||
lists:foldl(fun(H, Acc) -> Acc + (1 bsl H) end,
|
||||
0,
|
||||
lists:usort([H0, H1, H2, H3])).
|
||||
get_mask(H0, H1) ->
|
||||
case H0 == H1 of
|
||||
true ->
|
||||
1 bsl H0;
|
||||
false ->
|
||||
(1 bsl H0) + (1 bsl H1)
|
||||
end.
|
||||
|
||||
|
||||
%% This looks ugly and clunky, but in tests it was quicker than modifying an
|
||||
%% Erlang term like an array as it is passed around the loop
|
||||
|
||||
add_hashlist([], _S, S0, S1) ->
|
||||
IntSize = ?BLOOM_SIZE_BITS,
|
||||
IntSize = ?INTEGER_SIZE,
|
||||
<<S0:IntSize/integer, S1:IntSize/integer>>;
|
||||
add_hashlist([{_SegHash, TopHash}|T], SlotSplit, S0, S1) ->
|
||||
{Slot, H0, H1, H2, H3} = split_hash(TopHash, SlotSplit),
|
||||
Mask = get_mask(H0, H1, H2, H3),
|
||||
{Slot, H0, H1} = split_hash(TopHash, SlotSplit),
|
||||
Mask = get_mask(H0, H1),
|
||||
case Slot of
|
||||
0 ->
|
||||
add_hashlist(T, SlotSplit, S0 bor Mask, S1);
|
||||
|
|
@ -100,12 +98,12 @@ add_hashlist([{_SegHash, TopHash}|T], SlotSplit, S0, S1) ->
|
|||
end.
|
||||
|
||||
add_hashlist([], _S, S0, S1, S2, S3) ->
|
||||
IntSize = ?BLOOM_SIZE_BITS,
|
||||
IntSize = ?INTEGER_SIZE,
|
||||
<<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, H2, H3} = split_hash(TopHash, SlotSplit),
|
||||
Mask = get_mask(H0, H1, H2, H3),
|
||||
{Slot, H0, H1} = split_hash(TopHash, SlotSplit),
|
||||
Mask = get_mask(H0, H1),
|
||||
case Slot of
|
||||
0 ->
|
||||
add_hashlist(T, SlotSplit, S0 bor Mask, S1, S2, S3);
|
||||
|
|
@ -117,50 +115,104 @@ add_hashlist([{_SegHash, TopHash}|T], SlotSplit, S0, S1, S2, S3) ->
|
|||
add_hashlist(T, SlotSplit, S0, S1, S2, S3 bor Mask)
|
||||
end.
|
||||
|
||||
add_hashlist([], _S, S0, S1, S2, S3, S4, S5, S6, S7) ->
|
||||
IntSize = ?BLOOM_SIZE_BITS,
|
||||
add_hashlist([], _S, S0, S1, S2, S3, S4, S5, S6, S7, S8, S9,
|
||||
SA, SB, SC, SD, SE, SF) ->
|
||||
IntSize = ?INTEGER_SIZE,
|
||||
<<S0:IntSize/integer, S1:IntSize/integer,
|
||||
S2:IntSize/integer, S3:IntSize/integer,
|
||||
S4:IntSize/integer, S5:IntSize/integer,
|
||||
S6:IntSize/integer, S7:IntSize/integer>>;
|
||||
S6:IntSize/integer, S7:IntSize/integer,
|
||||
S8:IntSize/integer, S9:IntSize/integer,
|
||||
SA:IntSize/integer, SB:IntSize/integer,
|
||||
SC:IntSize/integer, SD:IntSize/integer,
|
||||
SE:IntSize/integer, SF:IntSize/integer>>;
|
||||
add_hashlist([{_SegHash, TopHash}|T],
|
||||
SlotSplit,
|
||||
S0, S1, S2, S3, S4, S5, S6, S7) ->
|
||||
{Slot, H0, H1, H2, H3} = split_hash(TopHash, SlotSplit),
|
||||
Mask = get_mask(H0, H1, H2, H3),
|
||||
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),
|
||||
case Slot of
|
||||
0 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0 bor Mask, S1, S2, S3, S4, S5, S6, S7);
|
||||
S0 bor Mask, S1, S2, S3, S4, S5, S6, S7, S8, S9,
|
||||
SA, SB, SC, SD, SE, SF);
|
||||
1 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1 bor Mask, S2, S3, S4, S5, S6, S7);
|
||||
S0, S1 bor Mask, S2, S3, S4, S5, S6, S7, S8, S9,
|
||||
SA, SB, SC, SD, SE, SF);
|
||||
2 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1, S2 bor Mask, S3, S4, S5, S6, S7);
|
||||
S0, S1, S2 bor Mask, S3, S4, S5, S6, S7, S8, S9,
|
||||
SA, SB, SC, SD, SE, SF);
|
||||
3 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1, S2, S3 bor Mask, S4, S5, S6, S7);
|
||||
S0, S1, S2, S3 bor Mask, S4, S5, S6, S7, S8, S9,
|
||||
SA, SB, SC, SD, SE, SF);
|
||||
4 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1, S2, S3, S4 bor Mask, S5, S6, S7);
|
||||
S0, S1, S2, S3, S4 bor Mask, S5, S6, S7, S8, S9,
|
||||
SA, SB, SC, SD, SE, SF);
|
||||
5 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1, S2, S3, S4, S5 bor Mask, S6, S7);
|
||||
S0, S1, S2, S3, S4, S5 bor Mask, S6, S7, S8, S9,
|
||||
SA, SB, SC, SD, SE, SF);
|
||||
6 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1, S2, S3, S4, S5, S6 bor Mask, S7);
|
||||
S0, S1, S2, S3, S4, S5, S6 bor Mask, S7, S8, S9,
|
||||
SA, SB, SC, SD, SE, SF);
|
||||
7 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1, S2, S3, S4, S5, S6, S7 bor Mask)
|
||||
S0, S1, S2, S3, S4, S5, S6, S7 bor Mask, S8, S9,
|
||||
SA, SB, SC, SD, SE, SF);
|
||||
8 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1, S2, S3, S4, S5, S6, S7, S8 bor Mask, S9,
|
||||
SA, SB, SC, SD, SE, SF);
|
||||
9 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1, S2, S3, S4, S5, S6, S7, S8, S9 bor Mask,
|
||||
SA, SB, SC, SD, SE, SF);
|
||||
10 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1, S2, S3, S4, S5, S6, S7, S8, S9,
|
||||
SA bor Mask, SB, SC, SD, SE, SF);
|
||||
11 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1, S2, S3, S4, S5, S6, S7, S8, S9,
|
||||
SA, SB bor Mask, SC, SD, SE, SF);
|
||||
12 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1, S2, S3, S4, S5, S6, S7, S8, S9,
|
||||
SA, SB, SC bor Mask, SD, SE, SF);
|
||||
13 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1, S2, S3, S4, S5, S6, S7, S8, S9,
|
||||
SA, SB, SC, SD bor Mask, SE, SF);
|
||||
14 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1, S2, S3, S4, S5, S6, S7, S8, S9,
|
||||
SA, SB, SC, SD, SE bor Mask, SF);
|
||||
15 ->
|
||||
add_hashlist(T,
|
||||
SlotSplit,
|
||||
S0, S1, S2, S3, S4, S5, S6, S7, S8, S9,
|
||||
SA, SB, SC, SD, SE, SF bor Mask)
|
||||
end.
|
||||
|
||||
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue