PHP 雪花算法收藏

需要注意的 $twepoch 变量一定要在项目初始化时重置为当前最新时间
该方法 存在一定问题使用3年左右 会存在 - 符号

### 雪花算法
class SnowFlake
{
    private static $lastTimestamp = 0;
    private static $lastSequence  = 0;
    private static $sequenceMask  = 4095;

    // 项目初始化时间毫秒戳 
    private static $twepoch       = 1715236393000;

    static function randStr($length)
    {
        return substr(str_shuffle("abcdefghijkmnpqrstuvwxyzABCDEFGHIJKMNPQRSTUVWXYZ23456789"), 0, $length);
    }

    static function randNumStr($length)
    {
        $chars = array(
            '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
        );
        $password = '';
        while (strlen($password) < $length) {
            $password .= $chars[rand(0, 9)];
        }
        return $password;
    }


    /**
     * 生成基于雪花算法的随机编号
     * @return int 分布式ID
     */
    static function snowFlake()
    {
        $timestamp = self::timeGen();

        if (self::$lastTimestamp == $timestamp) {
            self::$lastSequence = (self::$lastSequence + 1) & self::$sequenceMask;
            if (self::$lastSequence == 0) $timestamp = self::tilNextMillis(self::$lastTimestamp);
        } else {
            self::$lastSequence = 0;
        }
        self::$lastTimestamp = $timestamp;

        $snowFlakeId = (($timestamp - self::$twepoch) << 27) | (getmypid() << 12) | self::$lastSequence;

        return (string)$snowFlakeId;
    }

    /**
     * 反向解析雪花算法生成的编号
     * @param int|float $snowFlakeId
     * @return array
     */
    static function unSnowFlake($snowFlakeId)
    {
        $Binary = str_pad(decbin($snowFlakeId), 64, '0', STR_PAD_LEFT);
        return [
            'timestamp'    => bindec(substr($Binary, 0, 41)) + self::$twepoch,
            'dataCenterID' => bindec(substr($Binary, 42, 5)),
            'workerID'     => bindec(substr($Binary, 47, 5)),
            'sequence'     => bindec(substr($Binary, -12)),
        ];
    }

    /**
     * 等待下一毫秒的时间戳
     * @param $lastTimestamp
     * @return float
     */
    private static function tilNextMillis($lastTimestamp)
    {
        $timestamp = self::timeGen();
        while ($timestamp <= $lastTimestamp) {
            $timestamp = self::timeGen();
        }
        return $timestamp;
    }

    /**
     * 获取毫秒级时间戳
     * @return float
     */
    private static function timeGen()
    {
        return (float)sprintf('%.0f', microtime(true) * 1000);
    }
}