55 lines
1.0 KiB
Ruby
55 lines
1.0 KiB
Ruby
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# This file contains the Ruby code from book of
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# "Data Structures and Algorithms
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# with Object-Oriented Design Patterns in Ruby"
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# by Bruno R. Preiss.
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#
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# Copyright (c) 2004 by Bruno R. Preiss, P.Eng. All rights reserved.
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class QueueAsArray < Queue
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def initialize(size = 0)
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super()
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@array = Array.new(size)
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@head = 0
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@tail = size - 1
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end
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def purge
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while @count > 0
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@array[@head] = nil
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@head = @head + 1
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if @head == @array.length
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@head = 0
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end
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@count -= 1
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end
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end
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def head
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raise ContainerEmpty if @count == 0
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@array[@head]
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end
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def enqueue(obj)
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raise ContainerFull if @count == @array.length
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@tail = @tail + 1
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if @tail == @array.length
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@tail = 0
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end
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@array[@tail] = obj
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@count += 1
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end
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def dequeue
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raise ContainerEmpty if @count == 0
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result = @array[@head]
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@array[@head] = nil
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@head = @head + 1
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if @head == @array.length
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@head = 0
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end
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@count -= 1
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result
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end
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end
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