CPerfQueryWhere::_remove_braces

function _remove_braces($sql)
{
	while (true)
	{
		$new_sql = preg_replace("/\([ ]*(".$this->equation_regex."(?: AND ".$this->equation_regex.")*)[ ]*\)/i", "\1", $sql);
		if ($new_sql === null)
			break;

		if ($new_sql === $sql)
		{
			$new_sql = preg_replace("/\( \( (".$this->equation_regex."(?: OR ".$this->equation_regex.")*) \) \)/i", "( \1 )", trim($sql));
			if ($new_sql === null)
				break;

			if ($new_sql === $sql)
				break;
		}

		$sql = trim($new_sql);
	}
	return $sql;
}