<?phpclass Snowflake {// 定义Snowflake算法的各个参数private $workerIdBits = 5;private $datacenterIdBits = 5;private $sequenceBits = 12;private $workerIdShift;private $datacenterIdShift;private $timestampLeftShift;private $maxWorkerId;private $maxDatacenterId;private $sequenceMask;private $workerId;private $datacenterId;private $sequence = 0;private $lastTimestamp = -1;public function __construct($workerId, $datacenterId) {// 计算位偏移量$this->workerIdShift = $this->sequenceBits;$this->datacenterIdShift = $this->sequenceBits + $this->workerIdBits;$this->timestampLeftShift = $this->sequenceBits + $this->workerIdBits + $this->datacenterIdBits;// 计算最大ID$this->maxWorkerId = -1 ^ (-1 << $this->workerIdBits);$this->maxDatacenterId = -1 ^ (-1 << $this->datacenterIdBits);$this->sequenceMask = -1 ^ (-1 << $this->sequenceBits);// 初始化参数$this->workerId = $workerId;$this->datacenterId = $datacenterId;}// 生成下一个唯一IDpublic function generateId() {// 获取当前时间戳（毫秒级）$timestamp = floor(microtime(true) * 1000);// 如果当前时间小于上次生成ID的时间戳，则抛出异常if ($timestamp < $this->lastTimestamp) {throw new Exception("Invalid system clock!");}// 如果当前时间戳与上次时间戳相同，则自增序列号if ($timestamp == $this->lastTimestamp) {$this->sequence = ($this->sequence + 1) & $this->sequenceMask;// 如果序列号等于0，则需要进入下一毫秒重新生成IDif ($this->sequence == 0) {$timestamp = $this->waitNextMillis($this->lastTimestamp);}} else {$this->sequence = 0;}// 保存最后生成ID的时间戳$this->lastTimestamp = $timestamp;// 生成最终的唯一ID$uniqueId = (($timestamp << $this->timestampLeftShift) |($this->datacenterId << $this->datacenterIdShift) |($this->workerId << $this->workerIdShift) |$this->sequence);return $uniqueId;}// 阻塞到下一个毫秒，直到获得新的时间戳private function waitNextMillis($lastTimestamp) {$timestamp = floor(microtime(true) * 1000);while ($timestamp <= $lastTimestamp) {usleep(1000);$timestamp = floor(microtime(true) * 1000);}return $timestamp;}
}// 测试方法
$snowflake = new Snowflake(1, 1);
for ($i = 0; $i < 10; $i++) {$uniqueId = $snowflake->generateId();echo $uniqueId . "\n";
}?>

在上述代码中，我们创建了一个名为Snowflake的类，该类用于生成Snowflake算法的唯一ID。它具有以下主要属性和方法：

• __construct($workerId, $datacenterId)：初始化Snowflake算法的参数，包括工作节点ID(workerId)和数据中心ID(datacenterId)。
• generateId()：生成下一个唯一ID。
• waitNextMillis($lastTimestamp)：阻塞到下一个毫秒，直到获得新的时间戳。

在测试方法中，我们创建了一个Snowflake实例，并使用其generateId()方法生成了10个唯一ID，并打印出来。