站长资讯网本文给大家聊聊雪花算法的PHP实现，希望对需要的朋友有所帮助！
雪花算法的实现
最近看了下雪花算法，自己试着写了一下
<?php class SnowFlake { const TWEPOCH = 0; // 时间起始标记点，作为基准，一般取系统的最近时间（一旦确定不能变动） const WORKER_ID_BITS = 5; // 机器标识位数 const DATACENTER_ID_BITS = 5; // 数据中心标识位数 const SEQUENCE_BITS = 12; // 毫秒内自增位 private $workerId; // 工作机器ID private $datacenterId; // 数据中心ID private $sequence; // 毫秒内序列 private $maxWorkerId = -1 ^ (-1 << self::WORKER_ID_BITS); // 机器ID最大值 private $maxDatacenterId = -1 ^ (-1 << self::DATACENTER_ID_BITS); // 数据中心ID最大值 private $workerIdShift = self::SEQUENCE_BITS; // 机器ID偏左移位数 private $datacenterIdShift = self::SEQUENCE_BITS + self::WORKER_ID_BITS; // 数据中心ID左移位数 private $timestampLeftShift = self::SEQUENCE_BITS + self::WORKER_ID_BITS + self::DATACENTER_ID_BITS; // 时间毫秒左移位数 private $sequenceMask = -1 ^ (-1 << self::SEQUENCE_BITS); // 生成序列的掩码 private $lastTimestamp = -1; // 上次生产id时间戳 public function __construct($workerId, $datacenterId, $sequence = 0) { if ($workerId > $this->maxWorkerId || $workerId < 0) { throw new Exception("worker Id can't be greater than {$this->maxWorkerId} or less than 0"); } if ($datacenterId > $this->maxDatacenterId || $datacenterId < 0) { throw new Exception("datacenter Id can't be greater than {$this->maxDatacenterId} or less than 0"); } $this->workerId = $workerId; $this->datacenterId = $datacenterId; $this->sequence = $sequence; } public function createId() { $timestamp = $this->createTimestamp(); if ($timestamp < $this->lastTimestamp) {//当产生的时间戳小于上次的生成的时间戳时，报错 $diffTimestamp = bcsub($this->lastTimestamp, $timestamp); throw new Exception("Clock moved backwards. Refusing to generate id for {$diffTimestamp} milliseconds"); } if ($this->lastTimestamp == $timestamp) {//当生成的时间戳等于上次生成的时间戳的时候 $this->sequence = ($this->sequence + 1) & $this->sequenceMask;//序列自增一次 if (0 == $this->sequence) {//当序列为0时，重新生成最新的时间戳 $timestamp = $this->createNextTimestamp($this->lastTimestamp); } } else {//当生成的时间戳不等于上次的生成的时间戳的时候，序列归0 $this->sequence = 0; } $this->lastTimestamp = $timestamp; return (($timestamp - self::TWEPOCH) << $this->timestampLeftShift) | ($this->datacenterId << $this->datacenterIdShift) | ($this->workerId << $this->workerIdShift) | $this->sequence; } protected function createNextTimestamp($lastTimestamp) //生成一个大于等于 上次生成的时间戳 的时间戳 { $timestamp = $this->createTimestamp(); while ($timestamp <= $lastTimestamp) { $timestamp = $this->createTimestamp(); } return $timestamp; } protected function createTimestamp()//生成毫秒级别的时间戳 { return floor(microtime(true) * 1000); } } ?>
推荐学习：《PHP视频教程》
