require 'xmlscan/scanner'

module RSS
	
	class XMLScanParser < BaseParser
		
		private
		def listener
			XMLScanListener
		end

		def _parse
			begin
				XMLScan::XMLScanner.new(@listener).parse(@rss)
			rescue XMLScan::Error => e
				raise NotWellFormedError.new(e.lineno){e.message}
			end
		end
		
	end

	class XMLScanListener < BaseListener
		
		include XMLScan::Visitor
		include ListenerMixin

		ENTITIES = {
			'lt' => '<',
			'gt' => '>',
			'amp' => '&',
			'quot' => '"',
			'apos' => '\''
		}

    def on_xmldecl_version(str)
			@version = str
    end

    def on_xmldecl_encoding(str)
			@encoding = str
    end

    def on_xmldecl_standalone(str)
			@standalone = str
    end

    def on_xmldecl_end
			xmldecl(@version, @encoding, @standalone)
    end

		alias_method(:on_pi, :instruction)
		alias_method(:on_chardata, :text)
		alias_method(:on_cdata, :text)

    def on_etag(name)
      tag_end(name)
    end

    def on_entityref(ref)
			text(ENTITIES[ref])
    end

    def on_charref(code)
			text([code].pack('U'))
    end

		alias_method(:on_charref_hex, :on_charref)

    def on_stag(name)
			@attrs = {}
    end

    def on_attribute(name)
			@attrs[name] = @current_attr = ''
    end

    def on_attr_value(str)
			@current_attr << str
    end

    def on_attr_entityref(ref)
			@current_attr << ENTITIES[ref]
    end

    def on_attr_charref(code)
			@current_attr << [code].pack('U')
    end

		alias_method(:on_attr_charref_hex, :on_attr_charref)

    def on_stag_end(name)
			tag_start(name, @attrs)
    end

    def on_stag_end_empty(name)
			tag_start(name, @attrs)
			tag_end(name)
    end

	end

end