module REXML::Encoding

def decode(string)
  string.encode(::Encoding::UTF_8, @encoding)
end

def encode(string)
  string.encode(@encoding)
end

def encoding=(encoding)
  encoding = encoding.name if encoding.is_a?(Encoding)
  if encoding.is_a?(String)
    original_encoding = encoding
    encoding = find_encoding(encoding)
    unless encoding
      raise ArgumentError, "Bad encoding name #{original_encoding}"
    end
  end
  return false if defined?(@encoding) and encoding == @encoding
  if encoding
    @encoding = encoding.upcase
  else
    @encoding = 'UTF-8'
  end
  true
end

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