detect_encoding

# File lib/rexml/source.rb, line 123
    def detect_encoding
      buffer_encoding = @buffer.encoding
      detected_encoding = "UTF-8"
      begin
        @buffer.force_encoding("ASCII-8BIT")
        if @buffer[0, 2] == "\xfe\xff"
          @buffer[0, 2] = ""
          detected_encoding = "UTF-16BE"
        elsif @buffer[0, 2] == "\xff\xfe"
          @buffer[0, 2] = ""
          detected_encoding = "UTF-16LE"
        elsif @buffer[0, 3] == "\xef\xbb\xbf"
          @buffer[0, 3] = ""
          detected_encoding = "UTF-8"
        end
      ensure
        @buffer.force_encoding(buffer_encoding)
      end
      self.encoding = detected_encoding
    end