PHP は分散一意の ID を生成するために Snowflake を実装します

<?php
class Snowflake
{
    const EPOCH = 1543223810238;    // 起始时间戳，毫秒
    const SEQUENCE_BITS = 12;   //序号部分12位
    const SEQUENCE_MAX = -1 ^ (-1 << self::SEQUENCE_BITS);  // 序号最大值
    const WORKER_BITS = 10; // 节点部分10位
    const WORKER_MAX = -1 ^ (-1 << self::WORKER_BITS);  // 节点最大数值
    const TIME_SHIFT = self::WORKER_BITS + self::SEQUENCE_BITS; // 时间戳部分左偏移量
    const WORKER_SHIFT = self::SEQUENCE_BITS;   // 节点部分左偏移量
    protected $timestamp;   // 上次ID生成时间戳
    protected $workerId;    // 节点ID
    protected $sequence;    // 序号
    protected $lock;        // Swoole 互斥锁
    public function __construct($workerId)
    {
        if ($workerId < 0 || $workerId > self::WORKER_MAX) {
            trigger_error("Worker ID 超出范围");
            exit(0);
        }
        $this->timestamp = 0;
        $this->workerId = $workerId;
        $this->sequence = 0;
        $this->lock = new swoole_lock(SWOOLE_MUTEX);
    }
    /**
     * 生成ID
     * @return int
     */
    public function getId()
    {
        $this->lock->lock();    // 这里一定要记得加锁
        $now = $this->now();
        if ($this->timestamp == $now) {
            $this->sequence++;
            if ($this->sequence > self::SEQUENCE_MAX) {
                // 当前毫秒内生成的序号已经超出最大范围，等待下一毫秒重新生成
                while ($now <= $this->timestamp) {
                    $now = $this->now();
                }
            }
        } else {
            $this->sequence = 0;
        }
        $this->timestamp = $now;    // 更新ID生时间戳
        $id = (($now - self::EPOCH) << self::TIME_SHIFT) | ($this->workerId << self::WORKER_SHIFT) | $this->sequence;
        $this->lock->unlock();  //解锁
        return $id;
    }
    /**
     * 获取当前毫秒
     * @return string
     */
    public function now()
    {
        return sprintf("%.0f", microtime(true) * 1000);
    }
}

-1 ^ (-1 << self::SEQUENCE_BITS)

2**self::SEQUENCE_BITS - 1

(($now - self::EPOCH) << self::TIME_SHIFT) | ($this->workerId << self::WORKER_SHIFT) | $this->sequence;

0000 0000 0010  --左移0位--> 0000 0000 0010
0000 0000 0100  --左移4位--> 0000 0100 0000 --或操作-->1000 0100 0010
0000 0000 1000  --左移8位--> 1000 0000 0000

$snowflake = new Snowflake(1);
$chan = new chan(100000);
$n = 100000;
for ($i = 0; $i < $n; $i++) {
    go(function () use ($snowflake, $chan) {
        $id = $snowflake->getId();
        $chan->push($id);
    });
}
go(function () use ($chan, $n) {
    $arr = [];
    for ($i = 0; $i < $n; $i++) {
        $id = $chan->pop();  // PHP Swoole的channel一定要写在go(func)的协程里面！？
        if (in_array($id, $arr)) {
            exit("ID 已存在");
        }
        array_push($arr, $id);
    }
});
$chan->close();
echo "ok";