module RDoc::Text

def expand_tabs(text)
  expanded = []
  text.each_line do |line|
    nil while line.gsub!(/(?:\G|\r)((?:.{8})*?)([^\t\r\n]{0,7})\t/) do
      r = "#{$1}#{$2}#{' ' * (8 - $2.size)}"
      r = RDoc::Encoding.change_encoding r, text.encoding
      r
    end
    expanded << line
  end
  expanded.join
end