diff options
Diffstat (limited to 'lib/stdlib/src/gb_trees.erl')
| -rw-r--r-- | lib/stdlib/src/gb_trees.erl | 36 |
1 files changed, 31 insertions, 5 deletions
diff --git a/lib/stdlib/src/gb_trees.erl b/lib/stdlib/src/gb_trees.erl index 7069b61873..2cbfd8fd2a 100644 --- a/lib/stdlib/src/gb_trees.erl +++ b/lib/stdlib/src/gb_trees.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 @@ -102,6 +102,10 @@ %% approach is that it does not require the complete list of all %% elements to be built in memory at one time. %% +%% - iterator_from(K, T): returns an iterator that can be used for +%% traversing the entries of tree T with key greater than or +%% equal to K; see `next'. +%% %% - next(S): returns {X, V, S1} where X is the smallest key referred to %% by the iterator S, and S1 is the new iterator to be used for %% traversing the remaining entries, or the atom `none' if no entries @@ -117,7 +121,7 @@ update/3, enter/3, delete/2, delete_any/2, balance/1, is_defined/2, keys/1, values/1, to_list/1, from_orddict/1, smallest/1, largest/1, take_smallest/1, take_largest/1, - iterator/1, next/1, map/2]). + iterator/1, iterator_from/2, next/1, map/2]). %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% @@ -156,11 +160,10 @@ -type gb_tree_node(K, V) :: 'nil' | {K, V, gb_tree_node(K, V), gb_tree_node(K, V)}. --type gb_tree_node() :: gb_tree_node(_, _). -opaque tree(Key, Value) :: {non_neg_integer(), gb_tree_node(Key, Value)}. --opaque tree() :: tree(_, _). +-type tree() :: tree(_, _). -opaque iter(Key, Value) :: [gb_tree_node(Key, Value)]. --opaque iter() :: [gb_tree_node()]. +-type iter() :: iter(_, _). %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% @@ -529,6 +532,29 @@ iterator({_, _, L, _} = T, As) -> iterator(nil, As) -> As. +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +-spec iterator_from(Key, Tree) -> Iter when + Tree :: tree(Key, Value), + Iter :: iter(Key, Value). + +iterator_from(S, {_, T}) -> + iterator_1_from(S, T). + +iterator_1_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) -> 'none' | {Key, Value, Iter2} when Iter1 :: iter(Key, Value), Iter2 :: iter(Key, Value). |