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semaphore.rb
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semaphore.rb
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# semaphore.rb - efficient implementation of Fukumoto's semaphore
#
# Copyright 2008 MenTaLguY <mental@rydia.net>
#
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice,
# thi slist of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright notice
# this list of conditions and the following disclaimer in the documentatio
# and/or other materials provided with the distribution.
# * Neither the name of the Evan Phoenix nor the names of its contributors
# may be used to endorse or promote products derived from this software
# without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
class Semaphore
def initialize(initvalue = 0)
@channel = Rubinius::Channel.new
initvalue.times { @channel << nil }
end
def signal
@channel << nil
self
end
alias_method :up, :signal
alias_method :v, :signal
def wait
@channel.receive
self
end
alias_method :down, :wait
alias_method :p, :wait
def exclusive #:yields:
wait
begin
yield
ensure
signal
end
end
alias_method :synchronize, :exclusive
end