122 lines
2.9 KiB
PHP
122 lines
2.9 KiB
PHP
<?php
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namespace app\common\library;
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/**
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* 雪花算法ID生成器
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*/
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class Snowflake
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{
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// 起始时间戳（2023-01-01 00:00:00）
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const EPOCH = 1672531200000;
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// 机器ID位数
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const MACHINE_BITS = 10;
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// 序列号位数
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const SEQUENCE_BITS = 12;
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// 最大机器ID
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const MAX_MACHINE_ID = -1 ^ (-1 << self::MACHINE_BITS);
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// 最大序列号
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const MAX_SEQUENCE = -1 ^ (-1 << self::SEQUENCE_BITS);
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// 机器ID左移位数
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const MACHINE_SHIFT = self::SEQUENCE_BITS;
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// 时间戳左移位数
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const TIMESTAMP_SHIFT = self::SEQUENCE_BITS + self::MACHINE_BITS;
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// 机器ID（0-1023）
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private $machineId;
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// 最后时间戳
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private $lastTimestamp = -1;
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// 序列号
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private $sequence = 0;
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/**
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* 构造函数
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* @param int $machineId 机器ID
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*/
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public function __construct($machineId = 1)
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{
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if ($machineId < 0 || $machineId > self::MAX_MACHINE_ID) {
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throw new \InvalidArgumentException("机器ID必须在0-" . self::MAX_MACHINE_ID . "之间");
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}
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$this->machineId = $machineId;
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}
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/**
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* 生成ID
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* @return string
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*/
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public function generateId()
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{
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$timestamp = $this->getTimestamp();
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if ($timestamp < $this->lastTimestamp) {
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throw new \Exception("时钟回拨异常");
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}
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if ($timestamp == $this->lastTimestamp) {
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$this->sequence = ($this->sequence + 1) & self::MAX_SEQUENCE;
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if ($this->sequence == 0) {
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$timestamp = $this->waitNextMillis($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) << self::TIMESTAMP_SHIFT) |
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($this->machineId << self::MACHINE_SHIFT) |
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$this->sequence;
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}
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/**
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* 获取当前毫秒时间戳
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* @return int
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*/
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private function getTimestamp()
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{
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return (int)(microtime(true) * 1000);
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}
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/**
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* 等待下一毫秒
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* @param int $lastTimestamp
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* @return int
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*/
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private function waitNextMillis($lastTimestamp)
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{
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$timestamp = $this->getTimestamp();
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while ($timestamp <= $lastTimestamp) {
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usleep(100); // 休眠100微秒
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$timestamp = $this->getTimestamp();
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}
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return $timestamp;
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}
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/**
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* 解析ID
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* @param string $id
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* @return array
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*/
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public static function parseId($id)
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{
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$timestamp = ($id >> self::TIMESTAMP_SHIFT) + self::EPOCH;
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$machineId = ($id >> self::MACHINE_SHIFT) & self::MAX_MACHINE_ID;
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$sequence = $id & self::MAX_SEQUENCE;
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return [
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'timestamp' => $timestamp,
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'machine_id' => $machineId,
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'sequence' => $sequence,
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'generate_time' => date('Y-m-d H:i:s', $timestamp / 1000)
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];
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}
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} |