87 lines
2.0 KiB
PHP
87 lines
2.0 KiB
PHP
<?php
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namespace app\utils;
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/**
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* 雪花算法 - 分布式唯一ID生成器
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* Class Snowflake
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* @package app\utils
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*/
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class Snowflake
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{
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private const EPOCH = 1704067200000; // 2024-01-01 00:00:00 UTC
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private const WORKER_ID_BITS = 5;
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private const DATACENTER_ID_BITS = 5;
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private const SEQUENCE_BITS = 12;
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private int $workerId;
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private int $datacenterId;
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private int $sequence = 0;
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private int $lastTimestamp = -1;
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private static ?Snowflake $instance = null;
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public function __construct(int $workerId = 1, int $datacenterId = 1)
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{
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$this->workerId = $workerId & 0x1F;
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$this->datacenterId = $datacenterId & 0x1F;
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}
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/**
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* 获取单例实例
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*/
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public static function getInstance(): Snowflake
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{
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if (self::$instance === null) {
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self::$instance = new self(1, 1);
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}
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return self::$instance;
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}
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/**
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* 生成下一个ID
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*/
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public function nextId(): int
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{
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$timestamp = $this->currentTimeMillis();
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if ($timestamp === $this->lastTimestamp) {
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$this->sequence = ($this->sequence + 1) & 0xFFF;
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if ($this->sequence === 0) {
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$timestamp = $this->waitNextMillis($this->lastTimestamp);
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}
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} else {
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$this->sequence = 0;
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}
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$this->lastTimestamp = $timestamp;
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return (($timestamp - self::EPOCH) << 22)
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| ($this->datacenterId << 17)
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| ($this->workerId << 12)
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| $this->sequence;
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}
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/**
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* 生成字符串ID
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*/
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public function nextIdString(): string
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{
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return (string)$this->nextId();
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}
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private function currentTimeMillis(): int
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{
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return (int)(microtime(true) * 1000);
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}
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private function waitNextMillis(int $lastTimestamp): int
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{
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$timestamp = $this->currentTimeMillis();
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while ($timestamp <= $lastTimestamp) {
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$timestamp = $this->currentTimeMillis();
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}
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return $timestamp;
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}
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}
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