aboutsummaryrefslogtreecommitdiffstats
path: root/lib/stdlib/src/gb_sets.erl
diff options
context:
space:
mode:
Diffstat (limited to 'lib/stdlib/src/gb_sets.erl')
-rw-r--r--lib/stdlib/src/gb_sets.erl36
1 files changed, 27 insertions, 9 deletions
diff --git a/lib/stdlib/src/gb_sets.erl b/lib/stdlib/src/gb_sets.erl
index 0a26d0182d..d3fbd542f7 100644
--- a/lib/stdlib/src/gb_sets.erl
+++ b/lib/stdlib/src/gb_sets.erl
@@ -1,7 +1,7 @@
%%
%% %CopyrightBegin%
%%
-%% Copyright Ericsson AB 2001-2014. All Rights Reserved.
+%% Copyright Ericsson AB 2001-2015. 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
@@ -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:
@@ -207,21 +211,19 @@
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%%% gb_sets:set() in OTP 17 only.
-
-spec empty() -> Set when
- Set :: gb_sets:set().
+ Set :: set().
empty() ->
{0, nil}.
-spec new() -> Set when
- Set :: gb_sets:set().
+ Set :: set().
new() -> empty().
-spec is_empty(Set) -> boolean() when
- Set :: gb_sets:set().
+ Set :: set().
is_empty({0, nil}) ->
true;
@@ -229,7 +231,7 @@ is_empty(_) ->
false.
-spec size(Set) -> non_neg_integer() when
- Set :: gb_sets:set().
+ Set :: set().
size({Size, _}) ->
Size.
@@ -502,6 +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).