mirror of
https://github.com/RRQM/TouchSocket.git
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135 lines
4.9 KiB
C#
135 lines
4.9 KiB
C#
//------------------------------------------------------------------------------
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// 此代码版权（除特别声明或在XREF结尾的命名空间的代码）归作者本人若汝棋茗所有
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// 源代码使用协议遵循本仓库的开源协议及附加协议，若本仓库没有设置，则按MIT开源协议授权
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// CSDN博客：https://blog.csdn.net/qq_40374647
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// 哔哩哔哩视频：https://space.bilibili.com/94253567
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// Gitee源代码仓库：https://gitee.com/RRQM_Home
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// Github源代码仓库：https://github.com/RRQM
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// API首页：https://touchsocket.net/
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// 交流QQ群：234762506
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// 感谢您的下载和使用
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//------------------------------------------------------------------------------
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using System;
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namespace TouchSocket.Core;
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/// <summary>
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/// 雪花Id生成器(该代码来自网络)
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/// </summary>
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public class SnowflakeIdGenerator
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{
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private const int SequenceBits = 10;
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/// <summary>
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/// 一微秒内可以产生计数，如果达到该值则等到下一微妙在进行生成
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/// </summary>
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private const long SequenceMask = -1L ^ -1L << SequenceBits;
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private const int TimestampLeftShift = SequenceBits + WorkerIdBits;
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private const int WorkerIdBits = 4;
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//计数器字节数，10个字节用来保存计数码
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private const int WorkerIdShift = SequenceBits;
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private static long s_sequence = 0L;
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//机器Id
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private static long s_workerId;
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private readonly long m_twepoch = 687888001020L;
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private long m_lastTimestamp = -1L;
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static SnowflakeIdGenerator()
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{
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}
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/// <summary>
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/// 初始化 SnowflakeIdGenerator 类的新实例。
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/// </summary>
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/// <param name="workerId">工作机器的唯一标识符，用于区分不同的工作机器。</param>
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/// <exception cref="Exception">如果 workerId 大于最大工作机器ID或小于0，则抛出异常。</exception>
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public SnowflakeIdGenerator(long workerId)
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{
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// 检查 workerId 是否在有效范围内，如果不在，则抛出异常
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if (workerId > MaxWorkerId || workerId < 0)
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{
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throw new Exception(string.Format("worker Id can't be greater than {0} or less than 0 ", MaxWorkerId));
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}
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// 设置工作机器ID
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s_workerId = workerId;
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// 设置时间戳基准值，这是Snowflake算法中用到的一个重要参数
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this.m_twepoch = DateTimeOffset.UtcNow.Ticks - 10000;
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}
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/// <summary>
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/// 最大机器Id
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/// </summary>
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public static long MaxWorkerId { get; private set; } = -1L ^ (-1L << WorkerIdBits); //最大机器Id
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//唯一时间，这是一个避免重复的随机量，自行设定不要大于当前时间戳
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//机器码字节数。4个字节用来保存机器码(定义为Long类型会出现，最大偏移64位，所以左移64位没有意义)
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//机器码数据左移位数，就是后面计数器占用的位数
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//时间戳左移动位数就是机器码和计数器总字节数
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/// <summary>
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/// 获取Id
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/// </summary>
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/// <returns></returns>
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public long NextId()
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{
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lock (this)
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{
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var timestamp = this.TimeGen();
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if (this.m_lastTimestamp == timestamp)
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{ //同一微妙中生成Id
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s_sequence = (s_sequence + 1) & SequenceMask; //用&运算计算该微秒内产生的计数是否已经到达上限
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if (s_sequence == 0)
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{
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//一微妙内产生的Id计数已达上限，等待下一微妙
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timestamp = this.TillNextMillis(this.m_lastTimestamp);
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}
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}
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else
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{ //不同微秒生成Id
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s_sequence = 0; //计数清0
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}
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if (timestamp < this.m_lastTimestamp)
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{ //如果当前时间戳比上一次生成Id时时间戳还小，抛出异常，因为不能保证现在生成的Id之前没有生成过
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throw new Exception(string.Format("Clock moved backwards. Refusing to generate id for {0} milliseconds",
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this.m_lastTimestamp - timestamp));
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}
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this.m_lastTimestamp = timestamp; //把当前时间戳保存为最后生成Id的时间戳
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var nextId = (timestamp - this.m_twepoch << TimestampLeftShift) | s_workerId << WorkerIdShift | s_sequence;
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return nextId;
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}
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}
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/// <summary>
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/// 获取下一微秒时间戳
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/// </summary>
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/// <param name="lastTimestamp"></param>
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/// <returns></returns>
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private long TillNextMillis(long lastTimestamp)
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{
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var timestamp = this.TimeGen();
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while (timestamp <= lastTimestamp)
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{
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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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/// <summary>
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/// 生成当前时间戳
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/// </summary>
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/// <returns></returns>
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private long TimeGen()
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{
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return Environment.TickCount;
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}
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} |