diff options
Diffstat (limited to 'lib/stdlib/src/sets.erl')
| -rw-r--r-- | lib/stdlib/src/sets.erl | 76 |
1 files changed, 41 insertions, 35 deletions
diff --git a/lib/stdlib/src/sets.erl b/lib/stdlib/src/sets.erl index cd435ff49c..8adb9016e2 100644 --- a/lib/stdlib/src/sets.erl +++ b/lib/stdlib/src/sets.erl @@ -1,7 +1,7 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 2000-2014. All Rights Reserved. +%% Copyright Ericsson AB 2000-2018. All Rights Reserved. %% %% Licensed under the Apache License, Version 2.0 (the "License"); %% you may not use this file except in compliance with the License. @@ -37,7 +37,7 @@ -module(sets). %% Standard interface. --export([new/0,is_set/1,size/1,to_list/1,from_list/1]). +-export([new/0,is_set/1,size/1,is_empty/1,to_list/1,from_list/1]). -export([is_element/2,add_element/2,del_element/2]). -export([union/2,union/1,intersection/2,intersection/1]). -export([is_disjoint/2]). @@ -96,6 +96,12 @@ is_set(_) -> false. Set :: set(). size(S) -> S#set.size. +%% is_empty(Set) -> boolean(). +%% Return 'true' if Set is an empty set, otherwise 'false'. +-spec is_empty(Set) -> boolean() when + Set :: set(). +is_empty(S) -> S#set.size=:=0. + %% to_list(Set) -> [Elem]. %% Return the elements in Set as a list. -spec to_list(Set) -> List when @@ -128,14 +134,14 @@ is_element(E, S) -> Set2 :: set(Element). add_element(E, S0) -> Slot = get_slot(S0, E), - {S1,Ic} = on_bucket(fun (B0) -> add_bkt_el(E, B0, B0) end, S0, Slot), - maybe_expand(S1, Ic). - --spec add_bkt_el(T, [T], [T]) -> {[T], 0 | 1}. -add_bkt_el(E, [E|_], Bkt) -> {Bkt,0}; -add_bkt_el(E, [_|B], Bkt) -> - add_bkt_el(E, B, Bkt); -add_bkt_el(E, [], Bkt) -> {[E|Bkt],1}. + Bkt = get_bucket(S0, Slot), + case lists:member(E, Bkt) of + true -> + S0; + false -> + S1 = update_bucket(S0, Slot, [E | Bkt]), + maybe_expand(S1) + end. %% del_element(Element, Set) -> Set. %% Return Set but with Element removed. @@ -144,15 +150,28 @@ add_bkt_el(E, [], Bkt) -> {[E|Bkt],1}. Set2 :: set(Element). del_element(E, S0) -> Slot = get_slot(S0, E), - {S1,Dc} = on_bucket(fun (B0) -> del_bkt_el(E, B0) end, S0, Slot), - maybe_contract(S1, Dc). + Bkt = get_bucket(S0, Slot), + case lists:member(E, Bkt) of + false -> + S0; + true -> + S1 = update_bucket(S0, Slot, lists:delete(E, Bkt)), + maybe_contract(S1, 1) + end. --spec del_bkt_el(T, [T]) -> {[T], 0 | 1}. -del_bkt_el(E, [E|Bkt]) -> {Bkt,1}; -del_bkt_el(E, [Other|Bkt0]) -> - {Bkt1,Dc} = del_bkt_el(E, Bkt0), - {[Other|Bkt1],Dc}; -del_bkt_el(_, []) -> {[],0}. +%% update_bucket(Set, Slot, NewBucket) -> UpdatedSet. +%% Replace bucket in Slot by NewBucket +-spec update_bucket(Set1, Slot, Bkt) -> Set2 when + Set1 :: set(Element), + Set2 :: set(Element), + Slot :: non_neg_integer(), + Bkt :: [Element]. +update_bucket(Set, Slot, NewBucket) -> + SegI = ((Slot-1) div ?seg_size) + 1, + BktI = ((Slot-1) rem ?seg_size) + 1, + Segs = Set#set.segs, + Seg = element(SegI, Segs), + Set#set{segs = setelement(SegI, Segs, setelement(BktI, Seg, NewBucket))}. %% union(Set1, Set2) -> Set %% Return the union of Set1 and Set2. @@ -272,19 +291,6 @@ get_slot(T, Key) -> -spec get_bucket(set(), non_neg_integer()) -> term(). get_bucket(T, Slot) -> get_bucket_s(T#set.segs, Slot). -%% on_bucket(Fun, Hashdb, Slot) -> {NewHashDb,Result}. -%% Apply Fun to the bucket in Slot and replace the returned bucket. --spec on_bucket(fun((_) -> {[_], 0 | 1}), set(E), non_neg_integer()) -> - {set(E), 0 | 1}. -on_bucket(F, T, Slot) -> - SegI = ((Slot-1) div ?seg_size) + 1, - BktI = ((Slot-1) rem ?seg_size) + 1, - Segs = T#set.segs, - Seg = element(SegI, Segs), - B0 = element(BktI, Seg), - {B1, Res} = F(B0), %Op on the bucket. - {T#set{segs = setelement(SegI, Segs, setelement(BktI, Seg, B1))},Res}. - %% fold_set(Fun, Acc, Dictionary) -> Dictionary. %% filter_set(Fun, Dictionary) -> Dictionary. @@ -349,8 +355,8 @@ put_bucket_s(Segs, Slot, Bkt) -> Seg = setelement(BktI, element(SegI, Segs), Bkt), setelement(SegI, Segs, Seg). --spec maybe_expand(set(E), 0 | 1) -> set(E). -maybe_expand(T0, Ic) when T0#set.size + Ic > T0#set.exp_size -> +-spec maybe_expand(set(E)) -> set(E). +maybe_expand(T0) when T0#set.size + 1 > T0#set.exp_size -> T = maybe_expand_segs(T0), %Do we need more segments. N = T#set.n + 1, %Next slot to expand into Segs0 = T#set.segs, @@ -360,12 +366,12 @@ maybe_expand(T0, Ic) when T0#set.size + Ic > T0#set.exp_size -> {B1,B2} = rehash(B, Slot1, Slot2, T#set.maxn), Segs1 = put_bucket_s(Segs0, Slot1, B1), Segs2 = put_bucket_s(Segs1, Slot2, B2), - T#set{size = T#set.size + Ic, + T#set{size = T#set.size + 1, n = N, exp_size = N * ?expand_load, con_size = N * ?contract_load, segs = Segs2}; -maybe_expand(T, Ic) -> T#set{size = T#set.size + Ic}. +maybe_expand(T) -> T#set{size = T#set.size + 1}. -spec maybe_expand_segs(set(E)) -> set(E). maybe_expand_segs(T) when T#set.n =:= T#set.maxn -> |