feat: 增加 XdbVersion 结构体与读取方法

binding/csharp/IP2Region.Net.Test/XdbTest.cs

@@ -1,6 +1,4 @@
-using System.Buffers;
+using Xunit;
-using System.Buffers.Binary;
-using Xunit;
 
 namespace IP2Region.Net.Test;
 
@@ -10,67 +8,28 @@ public class XdbTest
     public async Task VersionIPV4_Ok()
     {
         var db = Path.Combine(AppContext.BaseDirectory, "TestData", $"ip2region_v4.xdb");
-        using var reader = File.OpenRead(db);
 
-        using var owner = MemoryPool<byte>.Shared.Rent(256);
+        var version = await XDB.Util.GetVersionAsync(db);
-        var length = await reader.ReadAsync(owner.Memory[0..256]);
+        Assert.Equal(3, version.Ver);
-        Assert.Equal(256, length);
+        Assert.Equal(1, version.CachePolice);
-
+        Assert.Equal("2025-09-06 02:24:16", version.CreatedTime.ToString("yyyy-MM-dd HH:mm:ss"));
-        var ver = BinaryPrimitives.ReadUInt16LittleEndian(owner.Memory.Span[..2]);
+        Assert.Equal((uint)955933, version.StartIndex);
-        Assert.Equal(3, ver);
+        Assert.Equal((uint)11042415, version.EndIndex);
-
+        Assert.Equal(4, version.IPVer);
-        var indexPolicy = BinaryPrimitives.ReadUInt16LittleEndian(owner.Memory.Span.Slice(2, 2));
+        Assert.Equal(4, version.BytesCount);
-        Assert.Equal(1, indexPolicy);
-
-        var createdAt = BinaryPrimitives.ReadUInt32LittleEndian(owner.Memory.Span.Slice(4, 4));
-        var dtm = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
-        dtm = dtm.AddSeconds(createdAt);
-        Assert.Equal("2025-09-06 02:24:16", dtm.ToString("yyyy-MM-dd HH:mm:ss"));
-
-        var startIndexPtr = BinaryPrimitives.ReadUInt32LittleEndian(owner.Memory.Span.Slice(8, 4));
-        Assert.Equal((uint)955933, startIndexPtr);
-
-        var endIndexPtr = BinaryPrimitives.ReadUInt32LittleEndian(owner.Memory.Span.Slice(12, 4));
-        Assert.Equal((uint)11042415, endIndexPtr);
-
-        // since IPv6 supporting
-        var ipVersion = BinaryPrimitives.ReadUInt16LittleEndian(owner.Memory.Span.Slice(16, 2));
-        Assert.Equal(4, ipVersion);
-
-        var runtimePtrBytes = BinaryPrimitives.ReadUInt16LittleEndian(owner.Memory.Span.Slice(18, 2));
-        Assert.Equal(4, runtimePtrBytes);
     }
 
     [Fact]
     public async Task VersionIPV6_Ok()
     {
         var db = Path.Combine(AppContext.BaseDirectory, "TestData", $"ip2region_v6.xdb");
-        using var reader = File.OpenRead(db);
+        var version = await XDB.Util.GetVersionAsync(db);
-
+        Assert.Equal(3, version.Ver);
-        using var owner = MemoryPool<byte>.Shared.Rent(256);
+        Assert.Equal(1, version.CachePolice);
-        var length = await reader.ReadAsync(owner.Memory[0..256]);
+        Assert.Equal("2025-10-17 04:41:04", version.CreatedTime.ToString("yyyy-MM-dd HH:mm:ss"));
-        Assert.Equal(256, length);
+        Assert.Equal((uint)3094259, version.StartIndex);
-
+        Assert.Equal((uint)36258303, version.EndIndex);
-        var ver = BinaryPrimitives.ReadUInt16LittleEndian(owner.Memory.Span[..2]);
+        Assert.Equal(6, version.IPVer);
-        Assert.Equal(3, ver);
+        Assert.Equal(4, version.BytesCount);
-
-        var indexPolicy = BinaryPrimitives.ReadUInt16LittleEndian(owner.Memory.Span.Slice(2, 2));
-        var createdAt = BinaryPrimitives.ReadUInt32LittleEndian(owner.Memory.Span.Slice(4, 4));
-        var dtm = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
-        dtm = dtm.AddSeconds(createdAt);
-        Assert.Equal("2025-10-17 04:41:04", dtm.ToString("yyyy-MM-dd HH:mm:ss"));
-
-        var startIndexPtr = BinaryPrimitives.ReadUInt32LittleEndian(owner.Memory.Span.Slice(8, 4));
-        Assert.Equal((uint)3094259, startIndexPtr);
-
-        var endIndexPtr = BinaryPrimitives.ReadUInt32LittleEndian(owner.Memory.Span.Slice(12, 4));
-        Assert.Equal((uint)36258303, endIndexPtr);
-
-        // since IPv6 supporting
-        var ipVersion = BinaryPrimitives.ReadUInt16LittleEndian(owner.Memory.Span.Slice(16, 2));
-        Assert.Equal(6, ipVersion);
-
-        var runtimePtrBytes = BinaryPrimitives.ReadUInt16LittleEndian(owner.Memory.Span.Slice(18, 2));
-        Assert.Equal(4, runtimePtrBytes);
     }
 }

binding/csharp/IP2Region.Net/XDB/Util.cs

@@ -1,3 +1,5 @@
+using System.Buffers;
+using System.Buffers.Binary;
 using System.Net;
 using System.Runtime.InteropServices;
 
@@ -10,7 +12,7 @@ public static class Util
         var address = IPAddress.Parse(ipAddress);
         return IpAddressToUInt32(address);
     }
-    
+
     public static uint IpAddressToUInt32(IPAddress ipAddress)
     {
         byte[] bytes = ipAddress.GetAddressBytes();
@@ -20,4 +22,55 @@ public static class Util
 
     public static uint GetMidIp(uint x, uint y)
         => (x & y) + ((x ^ y) >> 1);
+
+    public static async Task<XdbVersion> GetVersionAsync(string dbPath, CancellationToken token = default)
+    {
+        if (string.IsNullOrEmpty(dbPath))
+        {
+            throw new ArgumentNullException(nameof(dbPath));
+        }
+
+        if (!File.Exists(dbPath))
+        {
+            throw new FileNotFoundException("xdb file not fould.", dbPath);
+        }
+
+        XdbVersion ret = default;
+        using var reader = File.OpenRead(dbPath);
+        var buffer = ArrayPool<byte>.Shared.Rent(256);
+
+        try
+        {
+            var length = await reader.ReadAsync(buffer, 0, 256, token);
+            if (length == 256)
+            {
+                ret = Parse(buffer);
+            }
+        }
+        finally
+        {
+            ArrayPool<byte>.Shared.Return(buffer);
+        }
+
+        return ret;
+    }
+
+    private static XdbVersion Parse(ReadOnlySpan<byte> buffer)
+    {
+        var ret = new XdbVersion
+        {
+            Ver = BinaryPrimitives.ReadUInt16LittleEndian(buffer.Slice(0, 2)),
+            CachePolice = BinaryPrimitives.ReadUInt16LittleEndian(buffer.Slice(2, 2)),
+            StartIndex = BinaryPrimitives.ReadUInt32LittleEndian(buffer.Slice(8, 4)),
+            EndIndex = BinaryPrimitives.ReadUInt32LittleEndian(buffer.Slice(12, 4)),
+            IPVer = BinaryPrimitives.ReadUInt16LittleEndian(buffer.Slice(16, 2)),
+            BytesCount = BinaryPrimitives.ReadUInt16LittleEndian(buffer.Slice(18, 2))
+        };
+
+        var createdAt = BinaryPrimitives.ReadUInt32LittleEndian(buffer.Slice(4, 4));
+        var dtm = new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.FromHours(8));
+        ret.CreatedTime = dtm.AddSeconds(createdAt);
+
+        return ret;
+    }
 }

binding/csharp/IP2Region.Net/XDB/XdbVersion.cs

@@ -1,6 +1,6 @@
 namespace IP2Region.Net.XDB;
 
-public record struct XdbVersion
+public struct XdbVersion
 {
     /// <summary>
     /// 获得/设置 版本号