feat:support for concurrent file-based queries

binding/csharp/IP2Region.Net/Internal/ContentCacheStrategy.cs

@@ -0,0 +1,32 @@
+// 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.Internal.Abstractions;
+
+namespace IP2Region.Net.Internal;
+
+internal class ContentCacheStrategy : AbstractCacheStrategy
+{
+    private readonly ReadOnlyMemory<byte> _cacheData;
+
+    public ContentCacheStrategy(string xdbPath) : base(xdbPath)
+    {
+        _cacheData = base.GetData(0, (int)XdbFileStream.Length);
+        XdbFileStream.Close();
+        XdbFileStream.Dispose();
+    }
+
+    internal override ReadOnlyMemory<byte> GetVectorIndex(uint ip)
+    {
+        int idx = GetVectorIndexStartPos(ip);
+        return _cacheData.Slice(HeaderInfoLength + idx, VectorIndexSize);
+    }
+
+    internal override ReadOnlyMemory<byte> GetData(int offset, int length)
+    {
+        return _cacheData.Slice(offset, length);
+    }
+}