/// <summary>
/// Allocates memory for the managed representation of the array.
/// </summary>
/// <param name="unmanaged">The unmanaged array.</param>
/// <param name="numElements">The unmanaged element count.</param>
/// <returns>The managed array.</returns>
public static T *[]? AllocateContainerForManagedElements(TUnmanagedElement *unmanaged, int numElements)
{
if (unmanaged is null)
{
return(null);
}
return(new T *[numElements]);
}
/// <summary>
/// Initializes the <see cref="PointerArrayMarshaller{T, TUnmanagedElement}.ManagedToUnmanagedIn"/> marshaller.
/// </summary>
/// <param name="array">The array to be marshalled.</param>
/// <param name="buffer">The buffer that may be used for marshalling.</param>
/// <remarks>
/// The <paramref name="buffer"/> must not be movable - that is, it should not be
/// on the managed heap or it should be pinned.
/// </remarks>
public void FromManaged(T *[]?array, Span <TUnmanagedElement> buffer)
{
_allocatedMemory = null;
if (array is null)
{
_managedArray = null;
_span = default;
return;
}
_managedArray = array;
// Always allocate at least one byte when the array is zero-length.
if (array.Length <= buffer.Length)
{
_span = buffer[0..array.Length];
/// <summary>
/// Initializes the <see cref="SpanMarshaller{T, TUnmanagedElement}.ManagedToUnmanagedIn"/> marshaller.
/// </summary>
/// <param name="managed">Span to be marshalled.</param>
/// <param name="buffer">Buffer that may be used for marshalling.</param>
/// <remarks>
/// The <paramref name="buffer"/> must not be movable - that is, it should not be
/// on the managed heap or it should be pinned.
/// </remarks>
public void FromManaged(Span <T> managed, Span <TUnmanagedElement> buffer)
{
_allocatedMemory = null;
// Emulate the pinning behavior:
// If the span is over a null reference, then pass a null pointer.
if (Unsafe.IsNullRef(ref MemoryMarshal.GetReference(managed)))
{
_managedArray = null;
_span = default;
return;
}
_managedArray = managed;
if (managed.Length <= buffer.Length)
{
_span = buffer[0..managed.Length];
/// <summary>
/// Gets a source for the unmanaged elements in the array.
/// </summary>
/// <param name="unmanagedValue">The unmanaged array to get a source for.</param>
/// <param name="numElements">The unmanaged element count.</param>
/// <returns>The <see cref="ReadOnlySpan{TUnmanagedElement}"/> containing the unmanaged elements to marshal.</returns>
public static ReadOnlySpan <TUnmanagedElement> GetUnmanagedValuesSource(TUnmanagedElement *unmanagedValue, int numElements)
=> new ReadOnlySpan <TUnmanagedElement>(unmanagedValue, numElements);
/// <summary>
/// Gets a destination for the unmanaged elements in the array.
/// </summary>
/// <param name="unmanaged">The unmanaged allocation to get a destination for.</param>
/// <param name="numElements">The unmanaged element count.</param>
/// <returns>The <see cref="Span{TUnmanagedElement}"/> of unmanaged elements.</returns>
public static Span <TUnmanagedElement> GetUnmanagedValuesDestination(TUnmanagedElement *unmanaged, int numElements)
=> new Span <TUnmanagedElement>(unmanaged, numElements);
/// <summary> /// Frees memory for the unmanaged array. /// </summary> /// <param name="unmanaged">The unmanaged array.</param> public static void Free(TUnmanagedElement *unmanaged) => Marshal.FreeCoTaskMem((IntPtr)unmanaged);