Create UnmanagedExtensions.cs

src/TensorFlowNET.Core/Util/UnmanagedExtensions.cs

@@ -0,0 +1,94 @@
+using System;
+using System.IO;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using NumSharp.Backends.Unmanaged;
+
+namespace Tensorflow.Util
+{
+    public static class UnmanagedExtensions
+    {
+        //internally UnmanagedMemoryStream can't construct with null address.
+        private static readonly unsafe byte* _empty = (byte*) Marshal.AllocHGlobal(1);
+
+        /// <summary>
+        ///     Creates a memory stream based on given <paramref name="block"/>.
+        /// </summary>
+        /// <param name="block">The block to stream. Can be default/null.</param>
+        /// <remarks>There is no need to dispose the returned <see cref="UnmanagedMemoryStream"/></remarks>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static UnmanagedMemoryStream Stream(this UnmanagedMemoryBlock<byte> block)
+        {
+            unsafe
+            {
+                if (block.Address == null)
+                    return new UnmanagedMemoryStream(_empty, 0);
+                return new UnmanagedMemoryStream(block.Address, block.BytesCount);
+            }
+        }
+
+        /// <summary>
+        ///     Creates a memory stream based on given <paramref name="block"/>.
+        /// </summary>
+        /// <param name="block">The block to stream. Can be default/null.</param>
+        /// <param name="offset">Offset from the start of the block.</param>
+        /// <remarks>There is no need to dispose the returned <see cref="UnmanagedMemoryStream"/></remarks>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static UnmanagedMemoryStream Stream(this UnmanagedMemoryBlock<byte> block, long offset)
+        {
+            if (block.BytesCount - offset <= 0)
+                throw new ArgumentOutOfRangeException(nameof(offset));
+
+            unsafe
+            {
+                if (block.Address == null)
+                    return new UnmanagedMemoryStream(_empty, 0);
+                return new UnmanagedMemoryStream(block.Address + offset, block.BytesCount - offset);
+            }
+        }
+
+        /// <summary>
+        ///     Creates a memory stream based on given <paramref name="address"/>.
+        /// </summary>
+        /// <param name="address">The block to stream. Can be IntPtr.Zero.</param>
+        /// <param name="length">The length of the block in bytes.</param>
+        /// <remarks>There is no need to dispose the returned <see cref="UnmanagedMemoryStream"/></remarks>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static UnmanagedMemoryStream Stream(this IntPtr address, long length)
+        {
+            if (length <= 0)
+                throw new ArgumentOutOfRangeException(nameof(length));
+
+            unsafe
+            {
+                if (address == IntPtr.Zero)
+                    return new UnmanagedMemoryStream(_empty, 0);
+
+                // ReSharper disable once AssignNullToNotNullAttribute
+                return new UnmanagedMemoryStream((byte*) address, length);
+            }
+        }
+
+        /// <summary>
+        ///     Creates a memory stream based on given <paramref name="address"/>.
+        /// </summary>
+        /// <param name="address">The block to stream. Can be IntPtr.Zero.</param>
+        /// <param name="offset">Offset from the start of the block.</param>
+        /// <param name="length">The length of the block in bytes.</param>
+        /// <remarks>There is no need to dispose the returned <see cref="UnmanagedMemoryStream"/></remarks>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static UnmanagedMemoryStream Stream(this IntPtr address, long offset, long length)
+        {
+            if (length <= 0)
+                throw new ArgumentOutOfRangeException(nameof(length));
+
+            unsafe
+            {
+                if (address == IntPtr.Zero)
+                    return new UnmanagedMemoryStream(_empty, 0);
+
+                return new UnmanagedMemoryStream((byte*) address + offset, length);
+            }
+        }
+    }
+}