gistfile1.php

/**
* Generate regexp for naughty words censoring
* Depends on whether installed PHP version supports unicode properties
*
* @param string	$word			word template to be replaced
* @param bool	$use_unicode	whether or not to take advantage of PCRE supporting unicode
*
* @return string $preg_expr		regex to use with word censor
*/
function get_censor_preg_expression($word, $use_unicode = true)
{
	static $unicode_support = null;
	// Check whether PHP version supports unicode properties
	if (is_null($unicode_support))
	{
		$unicode_support = ((version_compare(PHP_VERSION, '5.1.0', '>=') || (version_compare(PHP_VERSION, '5.0.0-dev', '<=') && version_compare(PHP_VERSION, '4.4.0', '>='))) && @preg_match('/\p{L}/u', 'a') !== false) ? true : false;
	}
	// Unescape the asterisk to simplify further conversions
	$word = str_replace('\*', '*', preg_quote($word, '#'));
	if ($use_unicode && $unicode_support)
	{
		// Replace asterisk(s) inside the pattern, at the start and at the end of it with regexes
		$word = preg_replace(array('#(?<=[\p{Nd}\p{L}_])\*+(?=[\p{Nd}\p{L}_])#iu', '#^\*+#', '#\*+$#'), array('([\x20]*?|[\p{Nd}\p{L}_-]*?)', '[\p{Nd}\p{L}_-]*?', '[\p{Nd}\p{L}_-]*?'), $word);
		// Generate the final substitution
		$preg_expr = '#(?<![\p{Nd}\p{L}_-])(' . $word . ')(?![\p{Nd}\p{L}_-])#iu';
	}
	else
	{
		// Replace the asterisk inside the pattern, at the start and at the end of it with regexes
		$word = preg_replace(array('#(?<=\S)\*+(?=\S)#iu', '#^\*+#', '#\*+$#'), array('(\x20*?\S*?)', '\S*?', '\S*?'), $word);
		// Generate the final substitution
		$preg_expr = '#(?<!\S)(' . $word . ')(?!\S)#iu';
	}
	return $preg_expr;
}