SimplePie_Item::get_links

	 * @param string $rel The relationship of links to return
	 * @return array|null Links found for the item (strings)
	 */
	public function get_links($rel = 'alternate')
	{
		if (!isset($this->data['links']))
		{
			$this->data['links'] = array();
			foreach ((array) $this->get_item_tags(SIMPLEPIE_NAMESPACE_ATOM_10, 'link') as $link)
			{
				if (isset($link['attribs']['']['href']))
				{
					$link_rel = (isset($link['attribs']['']['rel'])) ? $link['attribs']['']['rel'] : 'alternate';
					$this->data['links'][$link_rel][] = $this->sanitize($link['attribs']['']['href'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($link));

				}
			}
			foreach ((array) $this->get_item_tags(SIMPLEPIE_NAMESPACE_ATOM_03, 'link') as $link)
			{
				if (isset($link['attribs']['']['href']))
				{
					$link_rel = (isset($link['attribs']['']['rel'])) ? $link['attribs']['']['rel'] : 'alternate';
					$this->data['links'][$link_rel][] = $this->sanitize($link['attribs']['']['href'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($link));
				}
			}
			if ($links = $this->get_item_tags(SIMPLEPIE_NAMESPACE_RSS_10, 'link'))
			{
				$this->data['links']['alternate'][] = $this->sanitize($links[0]['data'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($links[0]));
			}
			if ($links = $this->get_item_tags(SIMPLEPIE_NAMESPACE_RSS_090, 'link'))
			{
				$this->data['links']['alternate'][] = $this->sanitize($links[0]['data'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($links[0]));
			}
			if ($links = $this->get_item_tags(SIMPLEPIE_NAMESPACE_RSS_20, 'link'))
			{
				$this->data['links']['alternate'][] = $this->sanitize($links[0]['data'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($links[0]));
			}
			if ($links = $this->get_item_tags(SIMPLEPIE_NAMESPACE_RSS_20, 'guid'))
			{
				if (!isset($links[0]['attribs']['']['isPermaLink']) || strtolower(trim($links[0]['attribs']['']['isPermaLink'])) === 'true')
				{
					$this->data['links']['alternate'][] = $this->sanitize($links[0]['data'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($links[0]));
				}
			}

			$keys = array_keys($this->data['links']);
			foreach ($keys as $key)
			{
				if ($this->registry->call('Misc', 'is_isegment_nz_nc', array($key)))
				{
					if (isset($this->data['links'][SIMPLEPIE_IANA_LINK_RELATIONS_REGISTRY . $key]))
					{
						$this->data['links'][SIMPLEPIE_IANA_LINK_RELATIONS_REGISTRY . $key] = array_merge($this->data['links'][$key], $this->data['links'][SIMPLEPIE_IANA_LINK_RELATIONS_REGISTRY . $key]);
						$this->data['links'][$key] =& $this->data['links'][SIMPLEPIE_IANA_LINK_RELATIONS_REGISTRY . $key];
					}
					else
					{
						$this->data['links'][SIMPLEPIE_IANA_LINK_RELATIONS_REGISTRY . $key] =& $this->data['links'][$key];
					}
				}
				elseif (substr($key, 0, 41) === SIMPLEPIE_IANA_LINK_RELATIONS_REGISTRY)
				{
					$this->data['links'][substr($key, 41)] =& $this->data['links'][$key];
				}
				$this->data['links'][$key] = array_unique($this->data['links'][$key]);
			}
		}
		if (isset($this->data['links'][$rel]))
		{
			return $this->data['links'][$rel];
		}

		return null;