55 lines
1.0 KiB
Ruby
55 lines
1.0 KiB
Ruby
#
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# This is used for finding the gaps between a subset of elements in an array
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# and the original layout. We use this in Discourse to find gaps between posts.
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#
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# Note that we will only return a gap as 'before' or 'after', not both. We only
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# want to display the gap once.
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#
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class Gaps
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attr_reader :before, :after
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def initialize(subset, original)
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@before = {}
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@after = {}
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@subset = subset
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@original = original
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find_gaps
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end
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def empty?
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@before.size == 0 && @after.size == 0
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end
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def find_gaps
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return if @subset.nil? or @original.nil?
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i = j = 0
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gaps = {}
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current_gap = []
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while
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e1 = @subset[i]
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e2 = @original[j]
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if (e1 == e2)
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if current_gap.size > 0
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@before[e1] = current_gap.dup
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current_gap = []
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end
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i = i + 1
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else
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current_gap << e2
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end
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j = j + 1
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break if (i == @subset.size) || (j == @original.size)
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end
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@after[@subset[i-1]] = @original[j..-1] if j < @original.size
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end
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end
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