parse

# File actionpack/lib/action_controller/mime_type.rb, line 53
      def parse(accept_header)
        # keep track of creation order to keep the subsequent sort stable
        index = 0
        list = accept_header.split(/,/).map! do |i| 
          AcceptItem.new(index += 1, *i.split(/;\s*q=/))
        end.sort!

        # Take care of the broken text/xml entry by renaming or deleting it
        text_xml = list.index("text/xml")
        app_xml = list.index("application/xml")

        if text_xml && app_xml
          # set the q value to the max of the two
          list[app_xml].q = [list[text_xml].q, list[app_xml].q].max

          # make sure app_xml is ahead of text_xml in the list
          if app_xml > text_xml
            list[app_xml], list[text_xml] = list[text_xml], list[app_xml]
            app_xml, text_xml = text_xml, app_xml
          end

          # delete text_xml from the list
          list.delete_at(text_xml)
  
        elsif text_xml
          list[text_xml].name = "application/xml"
        end

        # Look for more specific xml-based types and sort them ahead of app/xml

        if app_xml
          idx = app_xml
          app_xml_type = list[app_xml]

          while(idx < list.length)
            type = list[idx]
            break if type.q < app_xml_type.q
            if type.name =~ /\+xml$/
              list[app_xml], list[idx] = list[idx], list[app_xml]
              app_xml = idx
            end
            idx += 1
          end
        end

        list.map! { |i| Mime::Type.lookup(i.name) }.uniq!
        list
      end