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PRELUDE
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SEMAPHOR.ST
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1987-06-17
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640b
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25 lines
Class Semaphore :List
| excessSignals |
[ new
excessSignals <- 0
| new: aNumber
excessSignals <- aNumber
| signal
<StartAtomic>. "start atomic action"
(self isEmpty)
ifTrue: [excessSignals <- excessSignals + 1]
ifFalse: [self removeFirst unblock].
<EndAtomic> "end atomic action"
| wait
<StartAtomic>. "start atomic actions"
(excessSignals = 0)
ifTrue: [self addLast: selfProcess.
selfProcess block]
ifFalse: [excessSignals <- excessSignals - 1].
<EndAtomic> "end atomic actions"
]