Class: Evidence::MergedStream

Inherits:
Object
  • Object
show all
Includes:
Stream
Defined in:
lib/evidence/stream.rb

Instance Method Summary collapse

Methods included from Stream

#|

Constructor Details

#initialize(streams, comparator) ⇒ MergedStream

Returns a new instance of MergedStream.



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# File 'lib/evidence/stream.rb', line 60

def initialize(streams, comparator)
  @comparator = comparator
  @heads = streams.map{|s| {stream: s}}
end

Instance Method Details

#each(&output) ⇒ Object 



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# File 'lib/evidence/stream.rb', line 69

def each(&output)
  pull_heads
  loop do
    if min = @heads.min{|a, b| @comparator.call(a[:element], b[:element])}
      output.call(min.delete(:element).tap{ pull_heads })
    else
      break if @heads.empty?
      pull_heads
    end
  end
end

#eos? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/evidence/stream.rb', line 65

def eos?
  @heads.empty?
end

#pull(stream) ⇒ Object 



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# File 'lib/evidence/stream.rb', line 85

def pull(stream)
  loop do
    return nil if stream.eos?
    if n = stream.first
      return n
    end
  end
end

#pull_heads ⇒ Object 



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# File 'lib/evidence/stream.rb', line 81

def pull_heads
  @heads.select!{|h| h[:element] ||= pull(h[:stream])}
end