natix.CompactDS.SArray.Rank1 C# (CSharp) Method

        public override int Rank1(int pos)
        {
            if (pos < 0 || this.Count1 == 0) {
                return 0;
            }
            int rank0_prev = 1 + (pos >> this.GetNumLowerBits ());
            int pos_prev = this.H.Select0 (rank0_prev);
            // Remember that $pos = rank0 + rank1 - 1$, thus $rank1 = pos - rank0 + 1$
            //int rank1_prevX = this.H.Rank1 (pos_prev); // prevcount = rank1
            int rank1_prev = pos_prev - rank0_prev + 1;
            //int rank1_nextX = this.H.Rank1 (this.H.Select0 (rank0_prev + 1));
            int pos_next = this.H.Select0 (rank0_prev + 1);
            int rank1_next = pos_next - rank0_prev;
            uint pos_masked = (uint)(this.get_mask () & pos);
            // Console.WriteLine ("xxxxx {0}", nextcount - prevcount);
            int count = rank1_next - rank1_prev;
            if (count < 16) {
                // if (true) {
                // sequential search
                int rank = rank1_prev;
                for (int i = 0; i < count; i++) {
                    var u = this.L [rank];
                    rank++;
                    if (u >= pos_masked) {
                        if (u > pos_masked) {
                            rank--;
                        }
                        break;
                    }
                }
                return rank;
            } else {
                // binary search
                //return 1 + GenericSearch.FindLast<int> ((int)pos_masked, this.L, rank1_prev, rank1_next);
                return 1 + Search.FindLast ((int)pos_masked, this.L, rank1_prev, rank1_next);
            }
        }