module REXML::Encoding

def find_encoding(name)
  case name
  when /\Ashift-jis\z/i
    return "SHIFT_JIS"
  when /\ACP-(\d+)\z/
    name = "CP#{$1}"
  when /\AUTF-8\z/i
    return name
  end
  begin
    ::Encoding::Converter.search_convpath(name, 'UTF-8')
  rescue ::Encoding::ConverterNotFoundError
    return nil
  end
  name
end