Sequence masks and code for old Hypercard fade

_1scatter.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Scramble_test {
	public class Scrambler {

		UInt32 mask = 0;
		UInt32 value = 1;
		UInt32 length = 0;

		public Scrambler (UInt32 Length) {
			SetLength(Length);
		}

		public IEnumerable<UInt32> Values () {
			if (length < 1) yield break;
			do {
				value = ((value & 1) != 0u) ? ((value >> 1) ^ mask) : (value >> 1);
				if (value <= length) yield return value - 1;
			} while (value != 1u);
			yield break;
		}

		private void SetLength (UInt32 Length) {
			mask = GetMask(Length);
			value = 1u;
			length = Length;
		}

		private UInt32 GetMask (UInt32 r) {
			// Jump table of magic numbers:
			if (r < 0x00000004) return 0x00000003u;
			if (r < 0x00000008) return 0x00000006u;
			if (r < 0x00000010) return 0x0000000Cu;
			if (r < 0x00000020) return 0x00000014u;
			if (r < 0x00000040) return 0x00000030u;
			if (r < 0x00000080) return 0x00000060u;
			if (r < 0x00000100) return 0x000000B8u;
			if (r < 0x00000200) return 0x00000110u;
			if (r < 0x00000400) return 0x00000240u;
			if (r < 0x00000800) return 0x00000500u;
			if (r < 0x00001000) return 0x00000CA0u;
			if (r < 0x00002000) return 0x00001B00u;
			if (r < 0x00004000) return 0x00003500u;
			if (r < 0x00008000) return 0x00006000u;
			if (r < 0x00010000) return 0x0000B400u;
			if (r < 0x00020000) return 0x00012000u;
			if (r < 0x00040000) return 0x00020400u;
			if (r < 0x00080000) return 0x00072000u;
			if (r < 0x00100000) return 0x00090000u;
			if (r < 0x00200000) return 0x00140000u;
			if (r < 0x00400000) return 0x00300000u;
			if (r < 0x00800000) return 0x00400000u;
			if (r < 0x01000000) return 0x00D80000u;
			if (r < 0x02000000) return 0x01200000u;
			if (r < 0x04000000) return 0x03880000u;
			if (r < 0x08000000) return 0x07200000u;
			if (r < 0x10000000) return 0x09000000u;
			if (r < 0x20000000) return 0x14000000u;
			if (r < 0x40000000) return 0x32800000u;
			if (r < 0x80000000) return 0x48000000u;
			if (r <= 0xFFFFFFFF) return 0xA3000000u;

			// if you need anymore than this, you should do your own paging.
			return 0xA3000000u; // this'll send your range checker nuts!
		}
	}
}

_2masks.cs

static long seqMasks [ /* n^(0..32) */ ] =
{0x0, 0x0, 0x03, 0x06, 0x0C, 0x14, 0x30, 0x60, 0xB8, 0x0110, 0x0240, 
0x0500, 0x0CA0, 0x1B00, 0x3500, 0x6000, 0xB400, 0x00012000, 0x00020400, 
0x00072000, 0x00090000, 0x00140000, 0x00300000, 0x00400000, 0x00D80000, 
0x01200000, 0x03880000, 0x07200000, 0x09000000, 0x14000000, 0x32800000, 
0x48000000, 0xA3000000
};