<?php

/**
 * rdfparser
 * class to parse newsfeeds into arrays
 * @author clemens krack
 * @link [url]http://www.tripdown.de[/url]
 * @access public
 **/

class rdfparser {
   var $_items; // array the items
   var $_may; // array what may be done
   var $_act; // string current active
   var $_index; // integer current index
   var $_url; // url to open

   /**
    * rdfparser::rdfparser()
    * 
    * @param $url url of  the feed
    * @return void
    **/

   function rdfparser($url) {
       $this->_url = $url;
   }

    /**
     * rdfparser::parse()
     * parses a newsfeed an returns an array containing the items.
     * @return array
     **/

    function parse() {
        $this->_items = array();
        $this->_index = 0;
        $this->_may['parse'] = false;
        $parser = xml_parser_create();

        xml_set_object($parser, $this);
        xml_set_element_handler($parser, "_startElement", "_endElement");
        xml_set_character_data_handler($parser, "_charHandler");

        $fp = fopen($this->_url, "r");

        while(!feof($fp)) {
            $line = fgets($fp, 4096);
            xml_parse($parser, $line);
        }

        fclose($fp);
        xml_parser_free($parser);
        return $this->_items;
    }



    function _startElement($parser, $name, $attrs) {
        // allow parsing chardata as soon as an element is opened
        $this->_may['char'] = true;

        if ($name=="ITEM") {
            // allow parsing as soon as an item element was opened
            $this->_may['parse'] = true;

            // one more item -> increment index
            $this->_index++;
            $this->_items[$this->_index] = Array('title' => '', 'link' => '', 'description' => '');

        } else if ($name=="TITLE") {
            // current active: title
            $this->_act = "TITLE";
        } else if($name=="LINK") {
            // current active: link
            $this->_act = "LINK";
        } else if($name=="DESCRIPTION") {
            // current active: description
            $this->_act = "DESCRIPTION";
        } else {
            // unknown tag, don't allow adding chardata
            $this->_may['char'] = false;
        }

        $this->_act = strtolower($this->_act);
    }



    function _endElement($parser, $name) {
        if($name=="ITEM") {
            // item tag closed: parsing not allowed
            $this->_may['parse'] = false;
        } elseif($name=="TITLE" || $name=="LINK" || $name="DESCRIPTION") {
            // datatag closed, we don't want different chardata
            $this->_may['char'] = false;
        }
    }



    function _charHandler($parser, $data) {
        $data = trim($data);

        if(!$this->_may['char'] OR !$this->_may['parse']) {
            return;
        }

        if (isset($this->_items[$this->_index][$this->_act])) {
            $this->_items[$this->_index][$this->_act] .= $data;
        } else {
            $this->_items[$this->_index][$this->_act] = $data;
        }
    }
} ?>