Added zstd frame compression option (about 25% less frame size for compression level = 2).

LiveScanServer/ZSTDDecompressor.cs

@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Runtime.InteropServices;
+using size_t = System.UIntPtr;
+
+namespace KinectServer
+{
+    static class ZSTDDecompressor
+    {
+        private const string dllName = "libzstd.dll";
+
+        [DllImport(dllName, CallingConvention = CallingConvention.Cdecl)]
+        public static extern ulong ZSTD_getDecompressedSize(IntPtr src, size_t srcSize);
+
+        [DllImport(dllName, CallingConvention = CallingConvention.Cdecl)]
+        public static extern size_t ZSTD_decompress(IntPtr dst, size_t dstSize, 
+            IntPtr src, size_t srcSize);
+
+        public static byte[] Decompress(byte []array)
+        {
+            int size = array.Count();
+            IntPtr ptr = Marshal.AllocHGlobal(size);
+            Marshal.Copy(array, 0, ptr, size);
+
+            int outSize = (int)ZSTD_getDecompressedSize(ptr, (size_t)size);
+            
+            IntPtr outPtr = Marshal.AllocHGlobal(outSize);
+            ZSTD_decompress(outPtr, (size_t)outSize, ptr, (size_t)size);
+
+            byte[] outArray = new byte[outSize];
+            Marshal.Copy(outPtr, outArray, 0, outSize);
+            
+            Marshal.FreeHGlobal(ptr);
+            Marshal.FreeHGlobal(outPtr);
+            return outArray;
+        }
+    }
+}