class PDF::Reader::WidthCalculator::TypeOneOrThree

def glyph_width(code_point)
  return 0 if code_point.nil? || code_point < 0
  return 0 if @font.widths.nil? || @font.widths.count == 0
  # in ruby a negative index is valid, and will go from the end of the array
  # which is undesireable in this case.
  first_char = @font.first_char
  if first_char && first_char <= code_point
    @font.widths.fetch(code_point - first_char, @missing_width.to_i).to_f
  else
    @missing_width.to_f
  end
end

def initialize(font)
  @font = font
  if fd = @font.font_descriptor
    @missing_width = fd.missing_width
  else
    @missing_width = 0
  end
end