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

        private void AddLowercaseRange(char chMin, char chMax, CultureInfo culture) {
            int i, iMax, iMid;
            char chMinT, chMaxT;
            LowerCaseMapping lc;

            for (i = 0, iMax = _lcTable.Length; i < iMax; ) {
                iMid = (i + iMax) / 2;
                if (_lcTable[iMid]._chMax < chMin)
                    i = iMid + 1;
                else
                    iMax = iMid;
            }

            if (i >= _lcTable.Length)
                return;

            for ( ; i < _lcTable.Length && (lc = _lcTable[i])._chMin <= chMax; i++) {
                if ((chMinT = lc._chMin) < chMin)
                    chMinT = chMin;

                if ((chMaxT = lc._chMax) > chMax)
                    chMaxT = chMax;

                switch (lc._lcOp) {
                    case LowercaseSet:
                        chMinT = (char)lc._data;
                        chMaxT = (char)lc._data;
                        break;
                    case LowercaseAdd:
                        chMinT += (char)lc._data;
                        chMaxT += (char)lc._data;
                        break;
                    case LowercaseBor:
                        chMinT |= (char)1;
                        chMaxT |= (char)1;
                        break;
                    case LowercaseBad:
                        chMinT += (char)(chMinT & 1);
                        chMaxT += (char)(chMaxT & 1);
                        break;
                }

                if (chMinT < chMin || chMaxT > chMax)
                    AddRange(chMinT, chMaxT);
            }
        }