%% From https://github.com/madnight/benchmarksgame/blob/9f5a20ba09e668a20bb0f9765b33071fa9bb3f1d/LICENSE
%%
%% Copyright © 2004-2008 Brent Fulgham, 2005-2017 Isaac Gouy
%%
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%% modification, are permitted provided that the following conditions are met:
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%%    Redistributions of source code must retain the above copyright notice,
%%    this list of conditions and the following disclaimer.
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%%    Redistributions in binary form must reproduce the above copyright notice,
%%    this list of conditions and the following disclaimer in the documentation
%%    and/or other materials provided with the distribution.
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%%    Neither the name of "The Computer Language Benchmarks Game" nor the name
%%    of "The Computer Language Shootout Benchmarks" nor the names of its
%%    contributors may be used to endorse or promote products derived from this
%%    software without specific prior written permission.
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% The Computer Language Benchmarks Game
% http://benchmarksgame.alioth.debian.org/
%%% Contributed by Jiri Isa

-module(threadring2).
-export([main/1, roundtrip/2]).

-define(RING, 503).

start(Token) ->
   H = lists:foldl(
      fun(Id, Pid) -> spawn(threadring2, roundtrip, [Id, Pid]) end,
      self(),
      lists:seq(?RING, 2, -1)),
   H ! Token,
   roundtrip(1, H).

roundtrip(Id, Pid) ->
   receive
      1 ->
         io:fwrite("~b~n", [Id]),
         erlang:halt();
      Token ->
         Pid ! Token - 1,
         roundtrip(Id, Pid)
   end.

main(Token) ->
   start(Token).