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Include gb_trees code

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The gb_trees in OTP16 doesn’t have iterative from support.  Included
here so that we can continue to use it regardless in Riak.
This commit is contained in:
Martin Sumner 2017-01-20 17:34:57 +00:00
parent 3d99036093
commit 9e32e228bb
1 changed files with 35 additions and 2 deletions
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37
src/leveled_tree.erl
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@ -178,10 +178,43 @@ tree_to_list(T) ->
gb_trees:to_list(T).
tree_iterator_from(K, T) ->
gb_trees:iterator_from(K, T).
% For OTP 16 compatibility with gb_trees
iterator_from(K, T).
tree_next(I) ->
gb_trees:next(I).
% For OTP 16 compatibility with gb_trees
next(I).
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.
next([{X, V, _, T} | As]) ->
{X, V, iterator(T, As)};
next([]) ->
none.
%% The iterator structure is really just a list corresponding to
%% the call stack of an in-order traversal. This is quite fast.
iterator({_, _, nil, _} = T, As) ->
[T | As];
iterator({_, _, L, _} = T, As) ->
iterator(L, [T | As]);
iterator(nil, As) ->
As.
%%%============================================================================
%%% Test