class Zip::PassThruDecompressor

def eof
  @read_so_far >= decompressed_size
end

def initialize(*args)
  super
  @read_so_far = 0
end

def read(length = nil, outbuf = '')
  return (length.nil? || length.zero? ? '' : nil) if eof
  if length.nil? || (@read_so_far + length) > decompressed_size
    length = decompressed_size - @read_so_far
  end
  @read_so_far += length
  input_stream.read(length, outbuf)
end