[erlang-questions] Real basic binary manipulation question

Steve Davis steven.charles.davis@REDACTED
Sat Jan 17 11:46:10 CET 2009

Problem - to decompress a binary where zeros are run-length encoded.
The following seems to work but also seems ugly and causes unnecessary

%% Decompress binary where Zeros are Run-Length Encoded
decompress(Bin) when is_binary(Bin) ->
	L = binary_to_list(Bin),
	F = fun(X, [H|T]) when H =:= expand -> lists:duplicate(X, 0) ++ T;
			(X, Acc) when X =:= 0 -> [expand] ++ Acc;
			(X, Acc) -> [X] ++ Acc
	Decompressed = lists:foldl(F, [], L),

Any bids on an improvement?

Thanks for any attention.

Side note: the erlang bit syntax is *amazing* when you actually get
down to doing something with IP packets

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