97 lines
3.4 KiB
C#
97 lines
3.4 KiB
C#
// Licensed to the .NET Foundation under one or more agreements.
|
|
// The .NET Foundation licenses this file to you under the MIT license.
|
|
// See the LICENSE file in the project root for more information.
|
|
|
|
#if NETSTANDARD2_1_OR_GREATER
|
|
|
|
using System;
|
|
using System.Buffers;
|
|
using System.Runtime.CompilerServices;
|
|
using System.Runtime.InteropServices;
|
|
using CommunityToolkit.HighPerformance.Helpers;
|
|
|
|
namespace CommunityToolkit.HighPerformance.Buffers.Internals;
|
|
|
|
/// <summary>
|
|
/// A custom <see cref="MemoryManager{T}"/> that can wrap arbitrary <see cref="object"/> instances.
|
|
/// </summary>
|
|
/// <typeparam name="T">The type of elements in the target memory area.</typeparam>
|
|
internal sealed class RawObjectMemoryManager<T> : MemoryManager<T>
|
|
{
|
|
/// <summary>
|
|
/// The target <see cref="object"/> instance.
|
|
/// </summary>
|
|
private readonly object instance;
|
|
|
|
/// <summary>
|
|
/// The initial offset within <see cref="instance"/>.
|
|
/// </summary>
|
|
private readonly IntPtr offset;
|
|
|
|
/// <summary>
|
|
/// The length of the target memory area.
|
|
/// </summary>
|
|
private readonly int length;
|
|
|
|
/// <summary>
|
|
/// Initializes a new instance of the <see cref="RawObjectMemoryManager{T}"/> class.
|
|
/// </summary>
|
|
/// <param name="instance">The target <see cref="object"/> instance.</param>
|
|
/// <param name="offset">The starting offset within <paramref name="instance"/>.</param>
|
|
/// <param name="length">The usable length within <paramref name="instance"/>.</param>
|
|
public RawObjectMemoryManager(object instance, IntPtr offset, int length)
|
|
{
|
|
this.instance = instance;
|
|
this.offset = offset;
|
|
this.length = length;
|
|
}
|
|
|
|
/// <inheritdoc/>
|
|
public override Span<T> GetSpan()
|
|
{
|
|
ref T r0 = ref ObjectMarshal.DangerousGetObjectDataReferenceAt<T>(this.instance, this.offset);
|
|
|
|
return MemoryMarshal.CreateSpan(ref r0, this.length);
|
|
}
|
|
|
|
/// <inheritdoc/>
|
|
public override unsafe MemoryHandle Pin(int elementIndex = 0)
|
|
{
|
|
if ((uint)elementIndex >= (uint)this.length)
|
|
{
|
|
ThrowArgumentOutOfRangeExceptionForInvalidElementIndex();
|
|
}
|
|
|
|
// Allocating a pinned handle for the array with fail and throw an exception
|
|
// if the array contains non blittable data. This is the expected behavior and
|
|
// the same happens when trying to pin a Memory<T> instance obtained through
|
|
// traditional means (eg. via the implicit T[] array conversion), if T is a
|
|
// reference type or a type containing some references.
|
|
GCHandle handle = GCHandle.Alloc(this.instance, GCHandleType.Pinned);
|
|
ref T r0 = ref ObjectMarshal.DangerousGetObjectDataReferenceAt<T>(this.instance, this.offset);
|
|
ref T r1 = ref Unsafe.Add(ref r0, (nint)(uint)elementIndex);
|
|
void* p = Unsafe.AsPointer(ref r1);
|
|
|
|
return new(p, handle);
|
|
}
|
|
|
|
/// <inheritdoc/>
|
|
public override void Unpin()
|
|
{
|
|
}
|
|
|
|
/// <inheritdoc/>
|
|
protected override void Dispose(bool disposing)
|
|
{
|
|
}
|
|
|
|
/// <summary>
|
|
/// Throws an <see cref="ArgumentOutOfRangeException"/> when the input index for <see cref="Pin"/> is not valid.
|
|
/// </summary>
|
|
private static void ThrowArgumentOutOfRangeExceptionForInvalidElementIndex()
|
|
{
|
|
throw new ArgumentOutOfRangeException("elementIndex", "The input element index was not in the valid range");
|
|
}
|
|
}
|
|
|
|
#endif |