init commit

2026-06-14 11:19:15 +08:00
parent e79a3815a5
commit c8e540d272
174 changed files with 60830 additions and 39 deletions
@@ -0,0 +1,128 @@
+using System;
+using System.Threading;
+
+namespace StandardScene.CommonTools
+{
+    public sealed class SnowflakeIdGenerator
+    {
+        // 默认起始时间戳：2026-01-01T00:00:00.000Z（Unix 毫秒）
+        // 如果你希望生成的数字更短，可以在构造函数里传入更“近”的 _epochMs（建议全系统统一）。
+        private const long DefaultEpochMs = 1767225600000L;
+        private const int WorkerIdBits = 5; // 机器ID所占的位数
+        private const int DatacenterIdBits = 5; // 数据中心ID所占的位数
+        private const int MaxWorkerId = -1 ^ (-1 << WorkerIdBits); // 最大机器ID
+        private const int MaxDatacenterId = -1 ^ (-1 << DatacenterIdBits); // 最大数据中心ID
+        private const int SequenceBits = 12; // 序列号所占的位数
+        private const int WorkerIdShift = SequenceBits; // 机器ID左移的位数
+        private const int DatacenterIdShift = SequenceBits + WorkerIdBits; // 数据中心ID左移的位数
+        private const int TimestampLeftShift = SequenceBits + WorkerIdBits + DatacenterIdBits; // 时间戳左移的位数
+        private const long SequenceMask = -1L ^ (-1L << SequenceBits); // 序列号的最大值
+
+        private const string Base62Alphabet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+
+        private readonly object _syncRoot = new object();
+        private readonly long _epochMs;
+        private readonly long _workerId; // 机器ID
+        private readonly long _datacenterId; // 数据中心ID
+        private long _sequence; // 序列号
+        private long _lastTimestamp = -1L; // 上次生成ID的时间戳
+
+        public SnowflakeIdGenerator(long workerId, long datacenterId, long? epochMs = null)
+        {
+            this._epochMs = epochMs ?? DefaultEpochMs;
+            if (this._epochMs > TimeGen())
+            {
+                throw new ArgumentException("_epochMs cannot be in the future.");
+            }
+            if (workerId is > MaxWorkerId or < 0)
+            {
+                throw new ArgumentException($"worker Id can't be greater than {MaxWorkerId} or less than 0");
+            }
+            if (datacenterId is > MaxDatacenterId or < 0)
+            {
+                throw new ArgumentException($"{datacenterId} can't be greater than {MaxDatacenterId} or less than 0");
+            }
+            this._workerId = workerId;
+            this._datacenterId = datacenterId;
+        }
+
+        public long NextId()
+        {
+            lock (_syncRoot)
+            {
+                long timestamp = TimeGen();
+                if (timestamp < _lastTimestamp)
+                {
+                    // 容忍系统时钟回拨：等待到追上 _lastTimestamp，避免直接抛异常把业务打崩。
+                    timestamp = TilNextMillis(_lastTimestamp);
+                }
+                if (_lastTimestamp == timestamp)
+                {
+                    _sequence = (_sequence + 1) & SequenceMask;
+                    if (_sequence == 0)
+                    {
+                        timestamp = TilNextMillis(_lastTimestamp);
+                    }
+                }
+                else
+                {
+                    _sequence = 0;
+                }
+                _lastTimestamp = timestamp;
+                long id = ((timestamp - _epochMs) << TimestampLeftShift)
+                          | (_datacenterId << DatacenterIdShift)
+                          | (_workerId << WorkerIdShift)
+                          | _sequence;
+                return id;
+            }
+        }
+
+        /// <summary>
+        /// 生成更短的字符串形式 ID（Base62 编码），便于显示/存储。
+        /// </summary>
+        public string NextIdBase62()
+        {
+            ulong value = unchecked((ulong)NextId());
+            return ToBase62(value);
+        }
+
+        private static long TilNextMillis(long lastTimestamp)
+        {
+            var spin = new SpinWait();
+            long timestamp;
+            do
+            {
+                spin.SpinOnce();
+                timestamp = TimeGen();
+            }
+            while (timestamp <= lastTimestamp);
+
+            return timestamp;
+        }
+
+        private static long TimeGen()
+        {
+            return DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
+        }
+
+        private static string ToBase62(ulong value)
+        {
+            if (value == 0)
+            {
+                return "0";
+            }
+
+            // 2^64-1 的 base62 最大长度为 11（因为 62^11 > 2^64）。
+            char[] buffer = new char[11];
+            int pos = buffer.Length;
+            while (value > 0)
+            {
+                ulong rem = value % 62;
+                value /= 62;
+                buffer[--pos] = Base62Alphabet[(int)rem];
+            }
+
+            return new string(buffer, pos, buffer.Length - pos);
+        }
+    }
+}