Class: CompositeReadIO

Inherits:
Object
  • Object
show all
Defined in:
lib/composite_io.rb

Overview

Concatenate together multiple IO objects into a single, composite IO object for purposes of reading as a single stream.

Usage:

crio = CompositeReadIO.new(StringIO.new('one'), StringIO.new('two'), StringIO.new('three'))
puts crio.read # => "onetwothree"

Instance Method Summary collapse

Constructor Details

#initialize(*ios) ⇒ CompositeReadIO

Create a new composite-read IO from the arguments, all of which should respond to #read in a manner consistent with IO.



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# File 'lib/composite_io.rb', line 18

def initialize(*ios)
  @ios = ios.flatten
end

Instance Method Details

#read(amount = nil, buf = nil) ⇒ Object

Read from the IO object, overlapping across underlying streams as necessary.



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# File 'lib/composite_io.rb', line 23

def read(amount = nil, buf = nil)
  buffer = buf || ''
  done = if amount; nil; else ''; end
  partial_amount = amount

  loop do
    result = done

    while !@ios.empty? && (result = @ios.first.read(partial_amount)) == done
      @ios.shift
    end

    buffer << result if result
    partial_amount -= result.length if partial_amount && result != done

    break if partial_amount && partial_amount <= 0
    break if result == done
  end

  if buffer.length > 0
    buffer
  else
    done
  end
end