添加项目文件。

Atomx.Utils/Extension/IdCodeExtension.cs

@@ -0,0 +1,37 @@
+using System.Text;
+
+namespace Atomx.Utils.Extension
+{
+    public static class IdCodeExtension
+    {
+        private static readonly char[] Base62Chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".ToCharArray();
+
+        /// <summary>
+        /// 将long类型ID编码为10位Base62邀请码
+        /// </summary>
+        public static string IdToCode(this long id)
+        {
+            ulong value = (ulong)id;
+            var sb = new StringBuilder();
+            for (int i = 0; i < 10; i++)
+            {
+                sb.Insert(0, Base62Chars[(int)(value % 62)]);
+                value /= 62;
+            }
+            return sb.ToString();
+        }
+
+        /// <summary>
+        /// 将10位Base62邀请码还原为long类型ID
+        /// </summary>
+        public static long CodeToId(this string code)
+        {
+            ulong value = 0;
+            foreach (var c in code)
+            {
+                value = value * 62 + (ulong)Array.IndexOf(Base62Chars, c);
+            }
+            return (long)value;
+        }
+    }
+}