def fix_escape( str )
  str.gsub(%r/\\(\d+|[nr])/) { |match|
    case $1
    when 'n': "\n"
    when 'r': "\r"
    else
      [$1.to_i(8)].pack('C')
    end
  }
end

str = %q{\\r\\n\\302\\267}

puts  fix_escape(str)