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51 lines
1.0 KiB
Ruby
51 lines
1.0 KiB
Ruby
# 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 Array
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attr_accessor :baseIndex
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alias_method :init, :initialize
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alias_method :getitem, :[]
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alias_method :setitem, :[]=
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def initialize(size = 0, baseIndex = 0)
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init(size, nil)
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@baseIndex = baseIndex
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end
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def length=(value)
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tmp = Array.new(value, nil)
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for i in 0 ... [length, value].min
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tmp.setitem(i, getitem(i))
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end
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clear
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setitem(value - 1, nil) if value > 0
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for i in 0 ... tmp.length
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setitem(i, tmp.getitem(i))
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end
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end
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protected :getitem, :setitem
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def getOffset(index)
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@baseIndex = 0 if @baseIndex.nil?
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raise IndexError if not (@baseIndex ... @baseIndex + length) === index
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index - @baseIndex
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end
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def [](index)
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getitem(getOffset(index))
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end
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def []=(index, value)
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setitem(getOffset(index), value)
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end
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end
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