/// <summary>
/// Determines whether two sequences overlap in memory and outputs the element offset.
/// </summary>
public static bool Overlaps <T>(this ReadOnlySpan <T> first, ReadOnlySpan <T> second, out int elementOffset)
{
if (first.IsEmpty || second.IsEmpty)
{
elementOffset = 0;
return(false);
}
IntPtr byteOffset = Unsafe.ByteOffset(
ref MemoryMarshal.GetReference(first),
ref MemoryMarshal.GetReference(second));
if (Unsafe.SizeOf <IntPtr>() == sizeof(int))
{
if ((uint)byteOffset < (uint)(first.Length * Unsafe.SizeOf <T>()) ||
(uint)byteOffset > (uint)-(second.Length * Unsafe.SizeOf <T>()))
{
if ((int)byteOffset % Unsafe.SizeOf <T>() != 0)
{
ThrowHelper.ThrowArgumentException_OverlapAlignmentMismatch();
}
elementOffset = (int)byteOffset / Unsafe.SizeOf <T>();
return(true);
}
else
{
elementOffset = 0;
return(false);
}
}
else
{
if ((ulong)byteOffset < (ulong)((long)first.Length * Unsafe.SizeOf <T>()) ||
(ulong)byteOffset > (ulong)-((long)second.Length * Unsafe.SizeOf <T>()))
{
if ((long)byteOffset % Unsafe.SizeOf <T>() != 0)
{
ThrowHelper.ThrowArgumentException_OverlapAlignmentMismatch();
}
elementOffset = (int)((long)byteOffset / Unsafe.SizeOf <T>());
return(true);
}
else
{
elementOffset = 0;
return(false);
}
}
}