From 8573f2f04e729a8de8e776abaae3470ad08ab9bc Mon Sep 17 00:00:00 2001
From: Argo Zhang <argo@live.ca>
Date: Tue, 4 Nov 2025 15:45:38 +0800
Subject: [PATCH] =?UTF-8?q?feat:=20=E5=A2=9E=E5=8A=A0=20Version=20?=
 =?UTF-8?q?=E9=80=82=E9=85=8D=20ipV6?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../Extensions/ServiceCollectionExtensions.cs |  8 ++++-
 binding/csharp/IP2Region.Net/XDB/Searcher.cs  | 31 +++++++++----------
 binding/csharp/IP2Region.Net/XDB/Version.cs   | 20 ++++++++++++
 3 files changed, 41 insertions(+), 18 deletions(-)
 create mode 100644 binding/csharp/IP2Region.Net/XDB/Version.cs

diff --git a/binding/csharp/IP2Region.Net/Extensions/ServiceCollectionExtensions.cs b/binding/csharp/IP2Region.Net/Extensions/ServiceCollectionExtensions.cs
index 980243a..b12278d 100644
--- a/binding/csharp/IP2Region.Net/Extensions/ServiceCollectionExtensions.cs
+++ b/binding/csharp/IP2Region.Net/Extensions/ServiceCollectionExtensions.cs
@@ -1,4 +1,10 @@
-using IP2Region.Net.Abstractions;
+// Copyright 2023 The Ip2Region Authors. All rights reserved.
+// Use of this source code is governed by a Apache2.0-style
+// license that can be found in the LICENSE file.
+// @Author Alan <lzh.shap@gmail.com>
+// @Date   2023/07/25
+
+using IP2Region.Net.Abstractions;
 using IP2Region.Net.XDB;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 
diff --git a/binding/csharp/IP2Region.Net/XDB/Searcher.cs b/binding/csharp/IP2Region.Net/XDB/Searcher.cs
index de29dc9..d684387 100644
--- a/binding/csharp/IP2Region.Net/XDB/Searcher.cs
+++ b/binding/csharp/IP2Region.Net/XDB/Searcher.cs
@@ -4,19 +4,18 @@
 // @Author Alan Lee <lzh.shap@gmail.com>
 // @Date   2023/07/23
 
-using System.Net;
-using System.Runtime.InteropServices;
-using System.Text;
 using IP2Region.Net.Abstractions;
 using IP2Region.Net.Internal;
 using IP2Region.Net.Internal.Abstractions;
+using System.Buffers.Binary;
+using System.Net;
+using System.Runtime.InteropServices;
+using System.Text;
 
 namespace IP2Region.Net.XDB;
 
 public class Searcher : ISearcher
 {
-    const int SegmentIndexSize = 14;
-
     private readonly AbstractCacheStrategy _cacheStrategy;
     public int IoCount => _cacheStrategy.IoCount;
 
@@ -40,36 +39,34 @@ public class Searcher : ISearcher
 
     public string? Search(uint ip)
     {
+        var version = new Version() { Length = 4, IndexSize = 14 };
         var index = _cacheStrategy.GetVectorIndex(ip);
         uint sPtr = MemoryMarshal.Read<uint>(index.Span);
         uint ePtr = MemoryMarshal.Read<uint>(index.Span.Slice(4));
 
-        var dataLen = 0;
+        uint dataLen = 0;
         uint dataPtr = 0;
         uint l = 0;
-        uint h = (ePtr -sPtr) / SegmentIndexSize;
+        uint h = (ePtr - sPtr) / (uint)version.IndexSize;
 
         while (l <= h)
         {
             var mid = Util.GetMidIp(l, h);
-            var pos = sPtr + mid * SegmentIndexSize;
+            var pos = sPtr + mid * version.IndexSize;
+            var buffer = _cacheStrategy.GetData((int)pos, version.IndexSize);
 
-            var buffer = _cacheStrategy.GetData((int)pos, SegmentIndexSize);
-            uint sip = MemoryMarshal.Read<uint>(buffer.Span);
-            uint eip = MemoryMarshal.Read<uint>(buffer.Span.Slice(4));
-
-            if (ip < sip)
+            if (ip < version.GetVectorIndexStartPos(buffer))
             {
                 h = mid - 1;
             }
-            else if (ip > eip)
+            else if (ip > version.GetVectorIndexEndPos(buffer))
             {
                 l = mid + 1;
             }
             else
             {
-                dataLen = MemoryMarshal.Read<ushort>(buffer.Span.Slice(8));
-                dataPtr = MemoryMarshal.Read<uint>(buffer.Span.Slice(10));
+                dataLen = BinaryPrimitives.ReadUInt16LittleEndian(buffer.Span.Slice(8));
+                dataPtr = BinaryPrimitives.ReadUInt32LittleEndian(buffer.Span.Slice(10));
                 break;
             }
         }
@@ -79,7 +76,7 @@ public class Searcher : ISearcher
             return default;
         }
 
-        var regionBuff = _cacheStrategy.GetData((int)dataPtr,dataLen);
+        var regionBuff = _cacheStrategy.GetData((int)dataPtr, (int)dataLen);
         return Encoding.UTF8.GetString(regionBuff.Span.ToArray());
     }
 }
\ No newline at end of file
diff --git a/binding/csharp/IP2Region.Net/XDB/Version.cs b/binding/csharp/IP2Region.Net/XDB/Version.cs
new file mode 100644
index 0000000..8a4e014
--- /dev/null
+++ b/binding/csharp/IP2Region.Net/XDB/Version.cs
@@ -0,0 +1,20 @@
+using System.Buffers.Binary;
+
+namespace IP2Region.Net.XDB;
+
+public struct Version
+{
+    public int IndexSize { get; set; }
+
+    public int Length { get; set; }
+
+    public uint GetVectorIndexStartPos(ReadOnlyMemory<byte> buffer)
+    {
+        return BinaryPrimitives.ReadUInt32LittleEndian(buffer.Span);
+    }
+
+    public uint GetVectorIndexEndPos(ReadOnlyMemory<byte> buffer)
+    {
+        return BinaryPrimitives.ReadUInt32LittleEndian(buffer.Slice(Length).Span);
+    }
+}