phpseclib\Net\SFTP::_comparator PHP Method

    function _comparator($a, $b)
    {
        switch (true) {
            case $a['filename'] === '.' || $b['filename'] === '.':
                if ($a['filename'] === $b['filename']) {
                    return 0;
                }
                return $a['filename'] === '.' ? -1 : 1;
            case $a['filename'] === '..' || $b['filename'] === '..':
                if ($a['filename'] === $b['filename']) {
                    return 0;
                }
                return $a['filename'] === '..' ? -1 : 1;
            case isset($a['type']) && $a['type'] === NET_SFTP_TYPE_DIRECTORY:
                if (!isset($b['type'])) {
                    return 1;
                }
                if ($b['type'] !== $a['type']) {
                    return -1;
                }
                break;
            case isset($b['type']) && $b['type'] === NET_SFTP_TYPE_DIRECTORY:
                return 1;
        }
        foreach ($this->sortOptions as $sort => $order) {
            if (!isset($a[$sort]) || !isset($b[$sort])) {
                if (isset($a[$sort])) {
                    return -1;
                }
                if (isset($b[$sort])) {
                    return 1;
                }
                return 0;
            }
            switch ($sort) {
                case 'filename':
                    $result = strcasecmp($a['filename'], $b['filename']);
                    if ($result) {
                        return $order === SORT_DESC ? -$result : $result;
                    }
                    break;
                case 'permissions':
                case 'mode':
                    $a[$sort] &= 07777;
                    $b[$sort] &= 07777;
                default:
                    if ($a[$sort] === $b[$sort]) {
                        break;
                    }
                    return $order === SORT_ASC ? $a[$sort] - $b[$sort] : $b[$sort] - $a[$sort];
            }
        }
    }