feat: allow sepecify output dir; process dir recursively

use cxxopts library to parse command line options

example/csharp/NeteaseCrypt.cs

@@ -14,7 +14,7 @@ namespace libncmdump_demo_cli
         private static extern IntPtr CreateNeteaseCrypt(IntPtr path);
 
         [DllImport(DLL_PATH, CallingConvention = CallingConvention.Cdecl)]
-        private static extern int Dump(IntPtr NeteaseCrypt);
+        private static extern int Dump(IntPtr NeteaseCrypt, IntPtr outputPath);
 
         [DllImport(DLL_PATH, CallingConvention = CallingConvention.Cdecl)]
         private static extern void FixMetadata(IntPtr NeteaseCrypt);
@@ -42,10 +42,17 @@ namespace libncmdump_demo_cli
         /// <summary>
         /// 启动转换过程。
         /// </summary>
+        /// <param name="OutputPath">指定一个路径输出，如果为空，则输出到原路径</param>
         /// <returns>返回一个整数，指示转储过程的结果。如果成功，返回0；如果失败，返回1。</returns>
-        public int Dump()
+        public int Dump(string OutputPath)
         {
-            return Dump(NeteaseCryptClass);
+            byte[] bytes = Encoding.UTF8.GetBytes(OutputPath);
+
+            IntPtr outputPtr = Marshal.AllocHGlobal(bytes.Length + 1);
+            Marshal.Copy(bytes, 0, outputPtr, bytes.Length);
+            Marshal.WriteByte(outputPtr, bytes.Length, 0);
+
+            return Dump(NeteaseCryptClass, outputPtr);
         }
 
         /// <summary>

example/csharp/Program.cs

@@ -14,7 +14,7 @@ namespace libncmdump_demo_cli
             NeteaseCrypt neteaseCrypt = new NeteaseCrypt(filePath);
 
             // 启动转换过程
-            int result = neteaseCrypt.Dump();
+            int result = neteaseCrypt.Dump("");  // 为空则输出到源
 
             // 修复元数据
             neteaseCrypt.FixMetadata();