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-rw-r--r--lib/stdlib/doc/src/gb_sets.xml13
-rw-r--r--lib/stdlib/src/gb_sets.erl24
-rw-r--r--lib/stdlib/test/sets_SUITE.erl44
-rw-r--r--lib/stdlib/test/sets_test_lib.erl5
4 files changed, 79 insertions, 7 deletions
diff --git a/lib/stdlib/doc/src/gb_sets.xml b/lib/stdlib/doc/src/gb_sets.xml
index ea96c14472..405bae5698 100644
--- a/lib/stdlib/doc/src/gb_sets.xml
+++ b/lib/stdlib/doc/src/gb_sets.xml
@@ -4,7 +4,7 @@
<erlref>
<header>
<copyright>
- <year>2001</year><year>2014</year>
+ <year>2001</year><year>2015</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
@@ -306,6 +306,17 @@
</desc>
</func>
<func>
+ <name name="iterator_from" arity="2"/>
+ <fsummary>Return an iterator for a set starting from a specified element</fsummary>
+ <desc>
+ <p>Returns an iterator that can be used for traversing the
+ entries of <c><anno>Set</anno></c>; see <c>next/1</c>.
+ The difference as compared to the iterator returned by
+ <c>iterator/1</c> is that the first element greater than
+ or equal to <c><anno>Element</anno></c> is returned.</p>
+ </desc>
+ </func>
+ <func>
<name name="largest" arity="1"/>
<fsummary>Return largest element</fsummary>
<desc>
diff --git a/lib/stdlib/src/gb_sets.erl b/lib/stdlib/src/gb_sets.erl
index 393fb07229..d3fbd542f7 100644
--- a/lib/stdlib/src/gb_sets.erl
+++ b/lib/stdlib/src/gb_sets.erl
@@ -137,6 +137,10 @@
%% approach is that it does not require the complete list of all
%% elements to be built in memory at one time.
%%
+%% - iterator_from(X, S): returns an iterator that can be used for
+%% traversing the elements of set S greater than or equal to X;
+%% see `next'.
+%%
%% - next(T): returns {X, T1} where X is the smallest element referred
%% to by the iterator T, and T1 is the new iterator to be used for
%% traversing the remaining elements, or the atom `none' if no
@@ -157,8 +161,8 @@
insert/2, add/2, delete/2, delete_any/2, balance/1, union/2,
union/1, intersection/2, intersection/1, is_disjoint/2, difference/2,
is_subset/2, to_list/1, from_list/1, from_ordset/1, smallest/1,
- largest/1, take_smallest/1, take_largest/1, iterator/1, next/1,
- filter/2, fold/3, is_set/1]).
+ largest/1, take_smallest/1, take_largest/1, iterator/1,
+ iterator_from/2, next/1, filter/2, fold/3, is_set/1]).
%% `sets' compatibility aliases:
@@ -500,6 +504,22 @@ iterator({_, L, _} = T, As) ->
iterator(nil, As) ->
As.
+-spec iterator_from(Element, Set) -> Iter when
+ Set :: set(Element),
+ Iter :: iter(Element).
+
+iterator_from(S, {_, T}) ->
+ iterator_from(S, T, []).
+
+iterator_from(S, {K, _, T}, As) when K < S ->
+ iterator_from(S, T, As);
+iterator_from(_, {_, nil, _} = T, As) ->
+ [T | As];
+iterator_from(S, {_, L, _} = T, As) ->
+ iterator_from(S, L, [T | As]);
+iterator_from(_, nil, As) ->
+ As.
+
-spec next(Iter1) -> {Element, Iter2} | 'none' when
Iter1 :: iter(Element),
Iter2 :: iter(Element).
diff --git a/lib/stdlib/test/sets_SUITE.erl b/lib/stdlib/test/sets_SUITE.erl
index c0cf1fc7e8..24f5d65f82 100644
--- a/lib/stdlib/test/sets_SUITE.erl
+++ b/lib/stdlib/test/sets_SUITE.erl
@@ -1,7 +1,7 @@
%%
%% %CopyrightBegin%
%%
-%% Copyright Ericsson AB 2004-2013. All Rights Reserved.
+%% Copyright Ericsson AB 2004-2015. All Rights Reserved.
%%
%% 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
@@ -28,7 +28,7 @@
create/1,add_element/1,del_element/1,
subtract/1,intersection/1,union/1,is_subset/1,
is_set/1,fold/1,filter/1,
- take_smallest/1,take_largest/1]).
+ take_smallest/1,take_largest/1, iterate/1]).
-include_lib("test_server/include/test_server.hrl").
@@ -48,7 +48,7 @@ suite() -> [{ct_hooks,[ts_install_cth]}].
all() ->
[create, add_element, del_element, subtract,
intersection, union, is_subset, is_set, fold, filter,
- take_smallest, take_largest].
+ take_smallest, take_largest, iterate].
groups() ->
[].
@@ -426,6 +426,44 @@ take_largest_3(S0, List0, M) ->
take_largest_3(S, List, M)
end.
+iterate(Config) when is_list(Config) ->
+ test_all(fun iterate_1/1).
+
+iterate_1(M) ->
+ case M(module, []) of
+ gb_sets -> iterate_2(M);
+ _ -> ok
+ end,
+ M(empty, []).
+
+iterate_2(M) ->
+ random:seed(1, 2, 42),
+ iter_set(M, 1000).
+
+iter_set(_M, 0) ->
+ ok;
+iter_set(M, N) ->
+ L = [I || I <- lists:seq(1, N)],
+ T = M(from_list, L),
+ L = lists:reverse(iterate_set(M, T)),
+ R = random:uniform(N),
+ S = lists:reverse(iterate_set(M, R, T)),
+ S = [E || E <- L, E >= R],
+ iter_set(M, N-1).
+
+iterate_set(M, Set) ->
+ I = M(iterator, Set),
+ iterate_set_1(M, M(next, I), []).
+
+iterate_set(M, Start, Set) ->
+ I = M(iterator_from, {Start, Set}),
+ iterate_set_1(M, M(next, I), []).
+
+iterate_set_1(_, none, R) ->
+ R;
+iterate_set_1(M, {E, I}, R) ->
+ iterate_set_1(M, M(next, I), [E | R]).
+
%%%
%%% Helper functions.
%%%
diff --git a/lib/stdlib/test/sets_test_lib.erl b/lib/stdlib/test/sets_test_lib.erl
index 86f009a8f9..772139406d 100644
--- a/lib/stdlib/test/sets_test_lib.erl
+++ b/lib/stdlib/test/sets_test_lib.erl
@@ -1,7 +1,7 @@
%%
%% %CopyrightBegin%
%%
-%% Copyright Ericsson AB 2004-2013. All Rights Reserved.
+%% Copyright Ericsson AB 2004-2015. All Rights Reserved.
%%
%% 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
@@ -34,7 +34,10 @@ new(Mod, Eq) ->
(is_empty, S) -> is_empty(Mod, S);
(is_set, S) -> Mod:is_set(S);
(is_subset, {S,Set}) -> is_subset(Mod, Eq, S, Set);
+ (iterator, S) -> Mod:iterator(S);
+ (iterator_from, {Start, S}) -> Mod:iterator_from(Start, S);
(module, []) -> Mod;
+ (next, I) -> Mod:next(I);
(singleton, E) -> singleton(Mod, E);
(size, S) -> Mod:size(S);
(subtract, {S1,S2}) -> subtract(Mod, S1, S2);
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-11 11:57:58 +0000