how to limit the amount of caracters? help...

Hi,
If someone here is willing to help me I would really appreciate
how to limit the amount of characters in the following php code, let say max 90 characters then should click read more link for details?

		$this->data['text_read_more'] = $this->language->get('text_read_more');
		$this->data['news'] = array();
		$results = $this->model_catalog_news->getNewsShorts($this->config->get('news_limit'));
		foreach ($results as $result) {
			$short_description = explode('.', html_entity_decode($result['description'])); 
			$this->data['news'][] = array(
				'title'             => $result['title'],
				'short_description' => $short_description[0],
				'href'              => $this->model_tool_seo_url->rewrite(HTTP_SERVER . 'index.php?route=page/news&news_id=' . $result['news_id'])
			);
		}

PHP:

the html code:

      <div style="border-bottom: 1px solid #DDDDDD; margin-bottom: 8px;">
        <?php echo $news_story['short_description']; ?> &hellip; <a href="<?php echo $news_story['href']; ?>"><?php echo $text_read_more; ?></a></p>
      </div>

Code (markup):

Thanks in advance

 

substr("$str",0,90)

 

$this->data['text_read_more'] = substr($this->data['text_read_more'],0,90) . " ... [<a href=''>Read More</a>]";

PHP:

Something like this?

 

Thank You, this already solved