System.Text.RegularExpressions.RegexCharClass.Canonicalize C# (CSharp) Method

        private void Canonicalize() {
            SingleRange CurrentRange;
            int i;
            int j;
            char last;
            bool Done;

            _canonical = true;
            _rangelist.Sort(0, _rangelist.Count, new SingleRangeComparer());

            //
            // Find and eliminate overlapping or abutting ranges
            //

            if (_rangelist.Count > 1) {
                Done = false;

                for (i = 1, j = 0; ; i++) {
                    for (last = ((SingleRange)_rangelist[j])._last; ; i++) {
                        if (i == _rangelist.Count || last == Lastchar) {
                            Done = true;
                            break;
                        }

                        if ((CurrentRange = (SingleRange)_rangelist[i])._first > last + 1)
                            break;

                        if (last < CurrentRange._last)
                            last = CurrentRange._last;
                    }

                    ((SingleRange)_rangelist[j])._last = last;

                    j++;

                    if (Done)
                        break;

                    if (j < i)
                        _rangelist[j] = _rangelist[i];
                }
                _rangelist.RemoveRange(j, _rangelist.Count - j);
            }
        }