Yea.Compression.BitArrayCompress.Write31Bits C# (CSharp) Method

        private void Write31Bits(List<uint> list, int index, uint val)
        {
            ResizeAsNeeded(list, index + 32);

            int off = (index%32);
            int pointer = index >> 5;

            if (pointer >= list.Count - 1)
                list.Add(0);

            ulong l = ((ulong) list[pointer] << 32) + list[pointer + 1];
            l |= (ulong) val << (33 - off);

            list[pointer] = (uint) (l >> 32);
            list[pointer + 1] = (uint) (l & 0xffffffff);
        }