Merge branch 'master' into rnn-dev

Author: AsakusaRinne

src/TensorFlowNET.Core/APIs/c_api.cs

@@ -55,10 +55,28 @@ public unsafe static byte[] ByteStringPiece(Buffer? handle)
         {
             if(handle is null){
                 return new byte[0];
-            }
             var data = handle.ToArray();
             return data;
         }
+          
+          public unsafe static byte[] ByteStringPieceFromNativeString(IntPtr handle)
+        {
+            if (handle == IntPtr.Zero)
+            {
+                return new byte[0];
+            }
+
+            byte* str_data = (byte*)handle.ToPointer();
+            List<byte> bytes = new List<byte>();
+            byte current = 255;
+            while (current != ((byte)'\0'))
+            {
+                current = *(str_data++);
+                bytes.Add(current);
+            }
+            var data = bytes.ToArray();
+            return data;
+        }
 
         [UnmanagedFunctionPointer(CallingConvention.Winapi)]
         public delegate void Deallocator(IntPtr data, IntPtr size, ref DeallocatorArgs args);