limit_chars.php

<?php

class Text {
	
	/**
	 * Limits a phrase to a given number of characters.
	 *
	 *     $text = Text::limit_chars($text);
	 *
	 * @param   string  $str            phrase to limit characters of
	 * @param   integer $limit          number of characters to limit to
	 * @param   string  $end_char       end character or entity
	 * @param   boolean $preserve_words enable or disable the preservation of words while limiting
	 * @return  string
	 */
	public static function limit_chars($str, $limit = 100, $end_char = NULL, $preserve_words = FALSE)
	{
		$end_char = ($end_char === NULL) ? '…' : $end_char;

		$limit = (int) $limit;

		if (trim($str) === '' OR mb_strlen($str) <= $limit)
			return $str;

		if ($limit <= 0)
			return $end_char;

		if ($preserve_words === FALSE)
			return rtrim(mb_substr($str, 0, $limit)).$end_char;

		// Don't preserve words. The limit is considered the top limit.
		// No strings with a length longer than $limit should be returned.
		if ( ! preg_match('/^.{0,'.$limit.'}\s/us', $str, $matches))
			return $end_char;

		return rtrim($matches[0]).((strlen($matches[0]) === strlen($str)) ? '' : $end_char);
	}
}