FluidXml\CssTranslator::tokenize PHP Метод

    protected static function tokenize($search, $replace, $id, &$xpath, &$stack, &$index)
    {
        // The search can return 0, 1 or more fund patterns.
        $matches_count = \preg_match_all($search, $xpath, $matches, \PREG_SET_ORDER | \PREG_OFFSET_CAPTURE);
        // \PREG_OFFSET_CAPTURE calculates offsets starting from the begining of the string $xpath.
        // Rewriting $xpath from left (first matches) creates a mismatch between the calculated offsets
        // and the actual ones. This problem can be avoided rewriting $xpath from right (last matches).
        for ($i = $matches_count - 1; $i >= 0; --$i) {
            $match = $matches[$i];
            // The count of the groups must exclude the entire recognized string entry.
            $groups_count = \count($match) - 1;
            // $match[0] is the entire recognized string.
            // $match[>0] are the captured groups.
            // $match[n][0] is the actual string.
            // $match[n][1] is the position of the string.
            list($pattern, $pattern_pos) = $match[0];
            $xpath = \substr_replace($xpath, "{{$id}{$index}}", $pattern_pos, \strlen($pattern));
            $groups_values = [];
            for ($ii = 1; $ii <= $groups_count; ++$ii) {
                // 0 is the group value, 1 is the group position.
                $groups_values[$ii] = $match[$ii][0];
            }
            $stack[$index] = [$replace, $groups_values, $pattern];
            ++$index;
        }
    }