/// <summary>
/// Initializes a new instance of the <see cref="Span2D{T}"/> struct with the specified parameters.
/// </summary>
/// <param name="pointer">The pointer to the first <typeparamref name="T"/> item to map.</param>
/// <param name="height">The height of the 2D memory area to map.</param>
/// <param name="width">The width of the 2D memory area to map.</param>
/// <param name="pitch">The pitch of the 2D memory area to map (the distance between each row).</param>
/// <exception cref="ArgumentOutOfRangeException">Thrown when one of the parameters are negative.</exception>
public unsafe Span2D(void *pointer, int height, int width, int pitch)
{
if (RuntimeHelpers.IsReferenceOrContainsReferences <T>())
{
ThrowHelper.ThrowArgumentExceptionForManagedType();
}
if (width < 0)
{
ThrowHelper.ThrowArgumentOutOfRangeExceptionForWidth();
}
if (height < 0)
{
ThrowHelper.ThrowArgumentOutOfRangeExceptionForHeight();
}
if (pitch < 0)
{
ThrowHelper.ThrowArgumentOutOfRangeExceptionForPitch();
}
OverflowHelper.EnsureIsInNativeIntRange(height, width, pitch);
#if SPAN_RUNTIME_SUPPORT
this.span = new Span <T>(pointer, height);
#else
this.Instance = null;
this.Offset = (IntPtr)pointer;
this.height = height;
#endif
this.width = width;
this.Stride = width + pitch;
}
/// <inheritdoc/>
public Memory <T> GetMemory <T>(int offset, int length)
where T : unmanaged
{
// Like in the other memory manager, calculate the absolute offset and length
int
absoluteOffset = this.offset + RuntimeHelpers.ConvertLength <TTo, TFrom>(offset),
absoluteLength = RuntimeHelpers.ConvertLength <TTo, TFrom>(length);
// Skip one indirection level and slice the original memory manager, if possible
if (typeof(T) == typeof(TFrom))
{
return((Memory <T>)(object) this.memoryManager.Memory.Slice(absoluteOffset, absoluteLength));
}
return(new ProxyMemoryManager <TFrom, T>(this.memoryManager, absoluteOffset, absoluteLength).Memory);
}
