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using System;

public class SnowflakeIdGenerator

{

    // 雪花算法的各个参数

    private static readonly long Epoch = new DateTime(2022, 1, 1).Ticks / 10000;  // 设置纪元时间（单位：毫秒）

    private static readonly int MachineIdBits = 10;  // 机器ID部分占用的位数

    private static readonly int SequenceBits = 12;   // 序列号部分占用的位数

    private static readonly long MaxMachineId = -1L ^ (-1L << MachineIdBits);  // 最大机器ID（1023）

    private static readonly long SequenceMask = -1L ^ (-1L << SequenceBits);   // 最大序列号（4095）

    private long lastTimestamp = -1L;  // 上次生成ID的时间戳

    private long machineId;            // 机器ID

    private long sequence = 0L;        // 序列号

    private readonly object lockObject = new object();

    // 构造函数：传入机器ID

    public SnowflakeIdGenerator(long machineId)

    {

        if (machineId > MaxMachineId || machineId < 0)

        {

            throw new ArgumentException($"Machine ID should be between 0 and {MaxMachineId}");

        }

        this.machineId = machineId;

    }

    // 生成下一个唯一的ID

    public long NextId()

    {

        lock (lockObject)

        {

            long timestamp = GetCurrentTimestamp();

            if (timestamp == lastTimestamp)

            {

                // 同一毫秒内，序列号加1

                sequence = (sequence + 1) & SequenceMask;

                if (sequence == 0)

                {

                    // 如果序列号溢出，等待下一毫秒

                    timestamp = WaitNextMillis(lastTimestamp);

                }

            }

            else

            {

                sequence = 0;

            }

            lastTimestamp = timestamp;

            // 组合成64位的ID

            return (timestamp - Epoch) << (MachineIdBits + SequenceBits)  // 时间戳部分

                 | (machineId << SequenceBits)                        // 机器ID部分

                 | sequence;                                          // 序列号部分

        }

    }

    // 获取当前时间戳（毫秒）

    private long GetCurrentTimestamp()

    {

        return DateTime.UtcNow.Ticks / 10000 - Epoch;  // 获取当前时间的毫秒数

    }

    // 等待下一毫秒

    private long WaitNextMillis(long lastTimestamp)

    {

        long timestamp = GetCurrentTimestamp();

        while (timestamp <= lastTimestamp)

        {

            timestamp = GetCurrentTimestamp();

        }

        return timestamp;

    }

}

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public class Program

{

    public static void Main()

    {

        var generator = new SnowflakeIdGenerator(1);  // 创建一个机器 ID 为 1 的 SnowflakeIdGenerator 实例

        for (int i = 0; i < 10; i++)

        {

            long id = generator.NextId();  // 生成一个新的唯一ID

            Console.WriteLine(id);          // 打印生成的ID

        }

    }

}