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Bloom filter: Handle hibernate situation in dense_bitmap.

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Erik Søe Sørensen 2012-09-25 15:17:24 +02:00
parent 12148a7af9
commit 1c6e0df15c
2 changed files with 10 additions and 3 deletions
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5
src/hanoidb_bloom.erl
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@ -196,7 +196,10 @@ bitmask_new(LogN) ->
bitmask_set(I, BM) -> bitmask_set(I, BM) ->
case element(1,BM) of case element(1,BM) of
array -> bitarray_set(I, BM); array -> bitarray_set(I, BM);
dense_bitmap_ets -> hanoidb_dense_bitmap:set(I, BM) dense_bitmap_ets -> hanoidb_dense_bitmap:set(I, BM);
dense_bitmap ->
%% Surprise - we need to mutate a built representation:
hanoidb_dense_bitmap:set(I, hanoidb_dense_bitmap:unbuild(BM))
end. end.
%%% Convert to external form. %%% Convert to external form.

8
src/hanoidb_dense_bitmap.erl
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@ -1,6 +1,6 @@
-module(hanoidb_dense_bitmap). -module(hanoidb_dense_bitmap).
-export([new/1, set/2, build/1, member/2]). -export([new/1, set/2, build/1, unbuild/1, member/2]).
-define(BITS_PER_CELL, 32). -define(BITS_PER_CELL, 32).
-define(REPR_NAME, dense_bitmap). -define(REPR_NAME, dense_bitmap).
@ -10,7 +10,6 @@ new(N) ->
Width = 1 + (N-1) div ?BITS_PER_CELL, Width = 1 + (N-1) div ?BITS_PER_CELL,
Value = erlang:make_tuple(Width+1, 0, [{1,?REPR_NAME}]), Value = erlang:make_tuple(Width+1, 0, [{1,?REPR_NAME}]),
ets:insert(Tab, Value), ets:insert(Tab, Value),
%io:format("DB| create(): ~p of width ~p\n", [Tab, Width]),
{dense_bitmap_ets, N, Width, Tab}. {dense_bitmap_ets, N, Width, Tab}.
%% Set a bit. %% Set a bit.
@ -27,6 +26,11 @@ build({dense_bitmap_ets, _, _, Tab}) ->
ets:delete(Tab), ets:delete(Tab),
Row. Row.
unbuild(Row) when element(1,Row)==?REPR_NAME ->
Tab = ets:new(dense_bitmap, [private, set]),
ets:insert(Tab, Row),
{dense_bitmap_ets, undefined, undefined, Tab}.
member(I, Row) when element(1,Row)==?REPR_NAME -> member(I, Row) when element(1,Row)==?REPR_NAME ->
Cell = 2 + I div ?BITS_PER_CELL, Cell = 2 + I div ?BITS_PER_CELL,
BitInCell = I rem ?BITS_PER_CELL, BitInCell = I rem ?BITS_PER_CELL,