mirror of https://github.com/dahall/Vanara.git
60 lines
2.5 KiB
C#
60 lines
2.5 KiB
C#
using System;
|
|
using System.Diagnostics.CodeAnalysis;
|
|
using System.Runtime.InteropServices;
|
|
using Vanara.Extensions;
|
|
|
|
namespace Vanara.InteropServices
|
|
{
|
|
/// <summary>A safe class that represents an object that is pinned in memory.</summary>
|
|
/// <seealso cref="System.IDisposable"/>
|
|
public class PinnedObject : IDisposable
|
|
{
|
|
private readonly int mOffset;
|
|
private GCHandle pinnedArray;
|
|
|
|
/// <summary>Initializes a new instance of the <see cref="PinnedObject"/> class.</summary>
|
|
/// <param name="obj">The object to pin.</param>
|
|
/// <param name="offset">The offset into the pinned bytes used to return a pointer.</param>
|
|
public PinnedObject(object obj, int offset = 0)
|
|
{
|
|
mOffset = offset;
|
|
SetObject(obj);
|
|
}
|
|
|
|
/// <summary>Creates a pinned object from a nullable structure.</summary>
|
|
/// <typeparam name="T">The type of the structure.</typeparam>
|
|
/// <param name="obj">The value to pin.</param>
|
|
/// <param name="offset">The offset into the pinned bytes used to return a pointer.</param>
|
|
/// <returns>A new instance of <see cref="PinnedObject"/>.</returns>
|
|
public static PinnedObject FromNullable<T>(T? obj, int offset = 0) where T : struct => obj.HasValue ? new PinnedObject(obj.Value, offset) : new PinnedObject(null, offset);
|
|
|
|
/// <summary>Initializes a new instance of the <see cref="PinnedObject"/> class.</summary>
|
|
[ExcludeFromCodeCoverage]
|
|
protected PinnedObject() { }
|
|
|
|
/// <summary>Gets a value indicating whether the object is no longer pinned.</summary>
|
|
/// <value><c>true</c> if the object is no longer pinned; otherwise, <c>false</c>.</value>
|
|
public bool IsInvalid => !pinnedArray.IsAllocated;
|
|
|
|
/// <summary>Get a pointer ( <see cref="IntPtr"/>) to the pinned memory of the object with any preset offset.</summary>
|
|
/// <param name="ap">The <see cref="PinnedObject"/> instance.</param>
|
|
/// <returns>The result of the conversion.</returns>
|
|
public static implicit operator IntPtr(PinnedObject ap) => !ap.IsInvalid ? ap.pinnedArray.AddrOfPinnedObject().Offset(ap.mOffset) : IntPtr.Zero;
|
|
|
|
/// <summary>Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.</summary>
|
|
public void Dispose()
|
|
{
|
|
if (pinnedArray.IsAllocated)
|
|
pinnedArray.Free();
|
|
}
|
|
|
|
/// <summary>Sets the object. This should only be called once per instance in the constructor.</summary>
|
|
/// <param name="obj">The object to pin.</param>
|
|
protected void SetObject(object obj)
|
|
{
|
|
if (obj != null)
|
|
pinnedArray = GCHandle.Alloc(obj, GCHandleType.Pinned);
|
|
}
|
|
}
|
|
}
|