125 lines
3.7 KiB
PHP
125 lines
3.7 KiB
PHP
<?php
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// application/common/library/Snowflake.php
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namespace app\common\library;
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class Snowflake
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{
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// 起始时间戳（2023-01-01）
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const EPOCH = 1672502400000;
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// 机器ID位数
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const WORKER_ID_BITS = 5;
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const DATACENTER_ID_BITS = 5;
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const SEQUENCE_BITS = 12;
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// 最大值
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const MAX_WORKER_ID = -1 ^ (-1 << self::WORKER_ID_BITS);
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const MAX_DATACENTER_ID = -1 ^ (-1 << self::DATACENTER_ID_BITS);
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const MAX_SEQUENCE = -1 ^ (-1 << self::SEQUENCE_BITS);
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// 移位
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const WORKER_ID_SHIFT = self::SEQUENCE_BITS;
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const DATACENTER_ID_SHIFT = self::SEQUENCE_BITS + self::WORKER_ID_BITS;
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const TIMESTAMP_LEFT_SHIFT = self::SEQUENCE_BITS + self::WORKER_ID_BITS + self::DATACENTER_ID_BITS;
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protected $workerId;
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protected $datacenterId;
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protected $sequence = 0;
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protected $lastTimestamp = -1;
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public function __construct($workerId = 1, $datacenterId = 1)
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{
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if ($workerId > self::MAX_WORKER_ID || $workerId < 0) {
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throw new \Exception("worker Id can't be greater than " . self::MAX_WORKER_ID . " or less than 0");
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}
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if ($datacenterId > self::MAX_DATACENTER_ID || $datacenterId < 0) {
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throw new \Exception("datacenter Id can't be greater than " . self::MAX_DATACENTER_ID . " or less than 0");
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}
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$this->workerId = $workerId;
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$this->datacenterId = $datacenterId;
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}
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public function nextId()
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{
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$timestamp = $this->timeGen();
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if ($timestamp < $this->lastTimestamp) {
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$diff = $this->lastTimestamp - $timestamp;
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throw new \Exception("Clock moved backwards. Refusing to generate id for {$diff} milliseconds");
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}
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if ($this->lastTimestamp == $timestamp) {
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$this->sequence = ($this->sequence + 1) & self::MAX_SEQUENCE;
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if ($this->sequence == 0) {
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$timestamp = $this->tilNextMillis($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) << self::TIMESTAMP_LEFT_SHIFT) |
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($this->datacenterId << self::DATACENTER_ID_SHIFT) |
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($this->workerId << self::WORKER_ID_SHIFT) |
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$this->sequence;
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}
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protected function tilNextMillis($lastTimestamp)
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{
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$timestamp = $this->timeGen();
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while ($timestamp <= $lastTimestamp) {
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$timestamp = $this->timeGen();
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}
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return $timestamp;
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}
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protected function timeGen()
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{
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return floor(microtime(true) * 1000);
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}
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/**
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* 解析雪花ID
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* @param int $id
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* @return array
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*/
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public static function parseId($id)
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{
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$binary = decbin($id);
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$binary = str_pad($binary, 64, '0', STR_PAD_LEFT);
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$timestamp = bindec(substr($binary, 0, 42));
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$timestamp = $timestamp + self::EPOCH;
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$datacenterId = bindec(substr($binary, 42, 5));
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$workerId = bindec(substr($binary, 47, 5));
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$sequence = bindec(substr($binary, 52, 12));
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return [
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'timestamp' => $timestamp,
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'datacenterId' => $datacenterId,
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'workerId' => $workerId,
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'sequence' => $sequence
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];
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}
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/**
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* 生成ID（单例模式）
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* @return int
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*/
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public static function generate()
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{
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static $instance = null;
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if (!$instance) {
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// 从配置获取workerId和datacenterId
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$workerId = config('snowflake.worker_id') ?: 1;
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$datacenterId = config('snowflake.datacenter_id') ?: 1;
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$instance = new self($workerId, $datacenterId);
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}
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return $instance->nextId();
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}
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} |