<?php

/**
 * This file is part of the Froxlor project.
 * Copyright (c) 2010 the Froxlor Team (see authors).
 *
 * For the full copyright and license information, please view the COPYING
 * file that was distributed with this source code. You can also view the
 * COPYING file online at http://files.froxlor.org/misc/COPYING.txt
 *
 * @copyright  (c) the authors
 * @author     Florian Aders <eleras@froxlor.org>
 * @license    GPLv2 http://files.froxlor.org/misc/COPYING.txt
 * @package    Functions
 *
 */

/**
 * Function which checks if a string is UTF8 encoded or not
 * @param string String to be checked
 * @return bool true if string is UTF8 encoded
 *
 * @author Florian Aders <eleras@froxlor.org>
 */

function isUtf8 ($string) {
	// From http://w3.org/International/questions/qa-forms-utf-8.html
	return preg_match('%^(?:
		[\x09\x0A\x0D\x20-\x7E]            # ASCII
		| [\xC2-\xDF][\x80-\xBF]            # non-overlong 2-byte
		|  \xE0[\xA0-\xBF][\x80-\xBF]        # excluding overlongs
		| [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}  # straight 3-byte
		|  \xED[\x80-\x9F][\x80-\xBF]        # excluding surrogates
		|  \xF0[\x90-\xBF][\x80-\xBF]{2}    # planes 1-3
		| [\xF1-\xF3][\x80-\xBF]{3}          # planes 4-15
		|  \xF4[\x80-\x8F][\x80-\xBF]{2}    # plane 16
		)*$%xs', $string
	);
}