diff options
Diffstat (limited to 'lib/dialyzer/test/r9c_tests_SUITE_data/src/mnesia/mnesia_frag_hash.erl')
| -rw-r--r-- | lib/dialyzer/test/r9c_tests_SUITE_data/src/mnesia/mnesia_frag_hash.erl | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/lib/dialyzer/test/r9c_tests_SUITE_data/src/mnesia/mnesia_frag_hash.erl b/lib/dialyzer/test/r9c_tests_SUITE_data/src/mnesia/mnesia_frag_hash.erl new file mode 100644 index 0000000000..19b97f8d61 --- /dev/null +++ b/lib/dialyzer/test/r9c_tests_SUITE_data/src/mnesia/mnesia_frag_hash.erl @@ -0,0 +1,118 @@ +%% ``The contents of this file are subject to the Erlang Public License, +%% Version 1.1, (the "License"); you may not use this file except in +%% compliance with the License. You should have received a copy of the +%% Erlang Public License along with this software. If not, it can be +%% retrieved via the world wide web at http://www.erlang.org/. +%% +%% Software distributed under the License is distributed on an "AS IS" +%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See +%% the License for the specific language governing rights and limitations +%% under the License. +%% +%% The Initial Developer of the Original Code is Ericsson Utvecklings AB. +%% Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings +%% AB. All Rights Reserved.'' +%% +%% $Id: mnesia_frag_hash.erl,v 1.1 2008/12/17 09:53:38 mikpe Exp $ +%% +%%%---------------------------------------------------------------------- +%%% Purpose : Implements hashing functionality for fragmented tables +%%%---------------------------------------------------------------------- + +%header_doc_include +-module(mnesia_frag_hash). +-behaviour(mnesia_frag_hash). + +%% Fragmented Table Hashing callback functions +-export([ + init_state/2, + add_frag/1, + del_frag/1, + key_to_frag_number/2, + match_spec_to_frag_numbers/2 + ]). + +%header_doc_include + +%impl_doc_include +-record(hash_state, {n_fragments, next_n_to_split, n_doubles}). + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +init_state(_Tab, State) when State == undefined -> + #hash_state{n_fragments = 1, + next_n_to_split = 1, + n_doubles = 0}. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +add_frag(State) when record(State, hash_state) -> + SplitN = State#hash_state.next_n_to_split, + P = SplitN + 1, + L = State#hash_state.n_doubles, + NewN = State#hash_state.n_fragments + 1, + State2 = case trunc(math:pow(2, L)) + 1 of + P2 when P2 == P -> + State#hash_state{n_fragments = NewN, + n_doubles = L + 1, + next_n_to_split = 1}; + _ -> + State#hash_state{n_fragments = NewN, + next_n_to_split = P} + end, + {State2, [SplitN], [NewN]}. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +del_frag(State) when record(State, hash_state) -> + P = State#hash_state.next_n_to_split - 1, + L = State#hash_state.n_doubles, + N = State#hash_state.n_fragments, + if + P < 1 -> + L2 = L - 1, + MergeN = trunc(math:pow(2, L2)), + State2 = State#hash_state{n_fragments = N - 1, + next_n_to_split = MergeN, + n_doubles = L2}, + {State2, [N], [MergeN]}; + true -> + MergeN = P, + State2 = State#hash_state{n_fragments = N - 1, + next_n_to_split = MergeN}, + {State2, [N], [MergeN]} + end. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +key_to_frag_number(State, Key) when record(State, hash_state) -> + L = State#hash_state.n_doubles, + A = erlang:phash(Key, trunc(math:pow(2, L))), + P = State#hash_state.next_n_to_split, + if + A < P -> + erlang:phash(Key, trunc(math:pow(2, L + 1))); + true -> + A + end. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +match_spec_to_frag_numbers(State, MatchSpec) when record(State, hash_state) -> + case MatchSpec of + [{HeadPat, _, _}] when tuple(HeadPat), size(HeadPat) > 2 -> + KeyPat = element(2, HeadPat), + case has_var(KeyPat) of + false -> + [key_to_frag_number(State, KeyPat)]; + true -> + lists:seq(1, State#hash_state.n_fragments) + end; + _ -> + lists:seq(1, State#hash_state.n_fragments) + end. + +%impl_doc_include + +has_var(Pat) -> + mnesia:has_var(Pat). |