mirror of https://github.com/dahall/Vanara.git
60 lines
2.7 KiB
C#
60 lines
2.7 KiB
C#
using System;
|
|
using System.Linq;
|
|
using System.Reflection;
|
|
using System.Runtime.CompilerServices;
|
|
using System.Runtime.InteropServices;
|
|
using Vanara.Extensions;
|
|
|
|
namespace Vanara.PInvoke
|
|
{
|
|
/// <summary>Helper methods for structures.</summary>
|
|
public static class StructHelper
|
|
{
|
|
/// <summary>Gets the address of a reference.</summary>
|
|
/// <typeparam name="T">The unmanaged value type to convert.</typeparam>
|
|
/// <param name="target">The target value.</param>
|
|
/// <returns>The address of <paramref name="target"/>.</returns>
|
|
/// <remarks>This address will only remain valid if the target value or its encapsulating type are pinned.</remarks>
|
|
public static IntPtr DangerousAddressOf<T>(ref T target) where T : unmanaged
|
|
{
|
|
unsafe
|
|
{
|
|
fixed (T* p = &target)
|
|
return (IntPtr)p;
|
|
}
|
|
}
|
|
|
|
/// <summary>Converts a field reference to array. Used when a structure defines an ANYSIZE array as the last field.</summary>
|
|
/// <typeparam name="T">The unmanaged type to convert.</typeparam>
|
|
/// <param name="fieldReference">A reference to the field value.</param>
|
|
/// <param name="count">The number of items in the array.</param>
|
|
/// <param name="offset">The offset from the field value at which to start extracting the array.</param>
|
|
/// <returns>An <paramref name="count"/> item array of values of <typeparamref name="T"/>.</returns>
|
|
/// <remarks>
|
|
/// Properties defined with this can only be safely used when the structure has been marshaled via a dynamic memory block and not
|
|
/// when marshaled directly.
|
|
/// </remarks>
|
|
[MethodImpl(MethodImplOptions.AggressiveInlining)]
|
|
public unsafe static T[] FieldToArray<T>(ref T fieldReference, int count, int offset = 0) where T : unmanaged
|
|
{
|
|
if (count == 0) return new T[0];
|
|
return DangerousAddressOf(ref fieldReference).ToArray<T>(count, offset);
|
|
}
|
|
|
|
/// <summary>Creates a new instance of <typeparamref name="T"/> with a size field set to the size of its unmanaged type.</summary>
|
|
/// <typeparam name="T">The type to return .</typeparam>
|
|
/// <param name="fieldName">
|
|
/// Name of the field which is assigned the size. If <see langword="null"/>, the first public or private field is used.
|
|
/// </param>
|
|
/// <returns>An initialized instance of <typeparamref name="T"/>.</returns>
|
|
public static T InitWithSize<T>(string fieldName = null) where T : new()
|
|
{
|
|
const BindingFlags bf = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic;
|
|
|
|
var fi = fieldName is null ? typeof(T).GetOrderedFields(bf).FirstOrDefault() : typeof(T).GetField(fieldName, bf);
|
|
var ret = (object)new T();
|
|
fi.SetValue(ret, Convert.ChangeType((uint)InteropExtensions.SizeOf<T>(), fi.FieldType));
|
|
return (T)ret;
|
|
}
|
|
}
|
|
} |