雪花算法

2025-12-26 11:47:14 +08:00
parent 8307b6c83d
commit f9de7a3a06
1 changed files with 122 additions and 0 deletions
--- a/application/common/library/Snowflake.php
+++ b/application/common/library/Snowflake.php
@@ -0,0 +1,122 @@
+<?php
+namespace app\common\library;
+
+/**
+ * 雪花算法ID生成器
+ */
+class Snowflake
+{
+    // 起始时间戳（2023-01-01 00:00:00）
+    const EPOCH = 1672531200000;
+
+    // 机器ID位数
+    const MACHINE_BITS = 10;
+
+    // 序列号位数
+    const SEQUENCE_BITS = 12;
+
+    // 最大机器ID
+    const MAX_MACHINE_ID = -1 ^ (-1 << self::MACHINE_BITS);
+
+    // 最大序列号
+    const MAX_SEQUENCE = -1 ^ (-1 << self::SEQUENCE_BITS);
+
+    // 机器ID左移位数
+    const MACHINE_SHIFT = self::SEQUENCE_BITS;
+
+    // 时间戳左移位数
+    const TIMESTAMP_SHIFT = self::SEQUENCE_BITS + self::MACHINE_BITS;
+
+    // 机器ID（0-1023）
+    private $machineId;
+
+    // 最后时间戳
+    private $lastTimestamp = -1;
+
+    // 序列号
+    private $sequence = 0;
+
+    /**
+     * 构造函数
+     * @param int $machineId 机器ID
+     */
+    public function __construct($machineId = 1)
+    {
+        if ($machineId < 0 || $machineId > self::MAX_MACHINE_ID) {
+            throw new \InvalidArgumentException("机器ID必须在0-" . self::MAX_MACHINE_ID . "之间");
+        }
+
+        $this->machineId = $machineId;
+    }
+
+    /**
+     * 生成ID
+     * @return string
+     */
+    public function generateId()
+    {
+        $timestamp = $this->getTimestamp();
+
+        if ($timestamp < $this->lastTimestamp) {
+            throw new \Exception("时钟回拨异常");
+        }
+
+        if ($timestamp == $this->lastTimestamp) {
+            $this->sequence = ($this->sequence + 1) & self::MAX_SEQUENCE;
+            if ($this->sequence == 0) {
+                $timestamp = $this->waitNextMillis($this->lastTimestamp);
+            }
+        } else {
+            $this->sequence = 0;
+        }
+
+        $this->lastTimestamp = $timestamp;
+
+        return (($timestamp - self::EPOCH) << self::TIMESTAMP_SHIFT) |
+            ($this->machineId << self::MACHINE_SHIFT) |
+            $this->sequence;
+    }
+
+    /**
+     * 获取当前毫秒时间戳
+     * @return int
+     */
+    private function getTimestamp()
+    {
+        return (int)(microtime(true) * 1000);
+    }
+
+    /**
+     * 等待下一毫秒
+     * @param int $lastTimestamp
+     * @return int
+     */
+    private function waitNextMillis($lastTimestamp)
+    {
+        $timestamp = $this->getTimestamp();
+        while ($timestamp <= $lastTimestamp) {
+            usleep(100); // 休眠100微秒
+            $timestamp = $this->getTimestamp();
+        }
+        return $timestamp;
+    }
+
+    /**
+     * 解析ID
+     * @param string $id
+     * @return array
+     */
+    public static function parseId($id)
+    {
+        $timestamp = ($id >> self::TIMESTAMP_SHIFT) + self::EPOCH;
+        $machineId = ($id >> self::MACHINE_SHIFT) & self::MAX_MACHINE_ID;
+        $sequence = $id & self::MAX_SEQUENCE;
+
+        return [
+            'timestamp' => $timestamp,
+            'machine_id' => $machineId,
+            'sequence' => $sequence,
+            'generate_time' => date('Y-m-d H:i:s', $timestamp / 1000)
+        ];
+    }
+}