chore: 更新逻辑

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

@@ -1,11 +1,117 @@
 using IP2Region.Net.XDB;
+using System.Buffers;
+using System.Buffers.Binary;
+using System.Net;
+using System.Text;
 using Xunit;
 
 namespace IP2Region.Net.Test;
 
 public class SearcherTest
 {
-    private readonly string _xdbPath = Path.Combine(AppContext.BaseDirectory, "TestData", "ip2region_v4.xdb");
+    private readonly string _xdbPath = Path.Combine(AppContext.BaseDirectory, "TestData", "ip2region_v6.xdb");
+
+    [Fact]
+    public void Test()
+    {
+        // 常量定义
+        // 每个 vector 索引项的字节数
+        var VectorIndexSize = 8;
+
+        // vector 索引的列数
+        var VectorIndexCols = 256;
+
+        // vector 索引段整个的字节数
+        var VectorIndexLength = 512;
+
+        //var ipAddress = IPAddress.Parse("240e:3b7:3272:d8d0:db09:c067:8d59:539e");
+        var ipAddress = IPAddress.Parse("2c0f:fda8:21::");
+        // [36,14,3,183,50,114,216,208,219,9,192,103,141,89,83,158]
+        //var ipAddress = IPAddress.Parse("58.251.27.201");
+        byte[] ip_bytes = ipAddress.GetAddressBytes();
+        //Array.Reverse(bytes);
+
+        //var ip = MemoryMarshal.Read<uint>(bytes);
+
+        var il0 = ip_bytes[0] & 0xFF;
+        var il1 = ip_bytes[1] & 0xFF;
+
+        var idx = il0 * VectorIndexCols * VectorIndexSize + il1 * VectorIndexSize;
+
+        var data = Read(256 + idx, VectorIndexSize);
+        var sPtr = BinaryPrimitives.ReadUInt32LittleEndian(data.Span);
+        var ePtr = BinaryPrimitives.ReadUInt32LittleEndian(data.Span.Slice(4));
+
+        var indexSize = 38;
+        var l = 0;
+        var h = (ePtr - sPtr) / indexSize;
+        var dataLen = 0;
+        var dataPtr = 0l;
+
+        var bytes = ip_bytes.Length;
+        var dBytes = ip_bytes.Length << 1;
+        var buff = new byte[indexSize];
+
+        while (l < h)
+        {
+            // 得到中间的索引项
+            int m = (int)(l + h) >> 1;
+
+            var p = (int)sPtr + m * indexSize;
+
+            buff = Read(p, buff.Length).ToArray();
+
+            var s1 = BinaryPrimitives.ReadUInt32BigEndian(ip_bytes);
+            var s = BinaryPrimitives.ReadUInt32BigEndian(buff.AsSpan().Slice(0, ip_bytes.Length).ToArray());
+            var e = BinaryPrimitives.ReadUInt32BigEndian(buff.AsSpan().Slice(ip_bytes.Length).ToArray());
+            if (s1 < s)
+            {
+                h = m - 1;
+            }
+            else if (s1 > e)
+            {
+                l = m + 1;
+            }
+            else
+            {
+                dataLen = BinaryPrimitives.ReadUInt16LittleEndian(buff.AsSpan().Slice(dBytes, 2));
+                dataPtr = BinaryPrimitives.ReadUInt32LittleEndian(buff.AsSpan().Slice(dBytes + 2));
+                break;
+            }
+        }
+
+        var regionBuff = Read((int)dataPtr, (int)dataLen);
+        var address = Encoding.UTF8.GetString(regionBuff.Span.ToArray());
+    }
+
+    private ReadOnlyMemory<byte> Read(int offset, int length)
+    {
+        int BufferSize = 4096;
+
+        var stream = new FileStream(_xdbPath, FileMode.Open, FileAccess.Read, FileShare.Read, BufferSize, useAsync: true);
+
+        byte[] buffer = ArrayPool<byte>.Shared.Rent(length);
+        int totalBytesRead = 0;
+        try
+        {
+            stream.Seek(offset, SeekOrigin.Begin);
+
+            int bytesRead;
+            do
+            {
+                int bytesToRead = Math.Min(BufferSize, length - totalBytesRead);
+                bytesRead = stream.Read(buffer, totalBytesRead, bytesToRead);
+                totalBytesRead += bytesRead;
+
+            } while (bytesRead > 0 && totalBytesRead < length);
+        }
+        finally
+        {
+            ArrayPool<byte>.Shared.Return(buffer);
+        }
+
+        return new ReadOnlyMemory<byte>(buffer, 0, totalBytesRead);
+    }
 
     [Theory]
     [InlineData("114.114.114.114")]