System.Text.RegularExpressions.RegexCode.OpcodeDescription C# (CSharp) Method

        internal string OpcodeDescription(int offset)
        {
            StringBuilder sb = new StringBuilder();
            int opcode = _codes[offset];

            sb.AppendFormat("{0:D6} ", offset);
            sb.Append(OpcodeBacktracks(opcode & Mask) ? '*' : ' ');
            sb.Append(OperatorDescription(opcode));
            sb.Append('(');

            opcode &= Mask;

            switch (opcode)
            {
                case One:
                case Notone:
                case Onerep:
                case Notonerep:
                case Oneloop:
                case Notoneloop:
                case Onelazy:
                case Notonelazy:
                    sb.Append("Ch = ");
                    sb.Append(RegexCharClass.CharDescription((char)_codes[offset + 1]));
                    break;

                case Set:
                case Setrep:
                case Setloop:
                case Setlazy:
                    sb.Append("Set = ");
                    sb.Append(RegexCharClass.SetDescription(_strings[_codes[offset + 1]]));
                    break;

                case Multi:
                    sb.Append("String = ");
                    sb.Append(_strings[_codes[offset + 1]]);
                    break;

                case Ref:
                case Testref:
                    sb.Append("Index = ");
                    sb.Append(_codes[offset + 1]);
                    break;

                case Capturemark:
                    sb.Append("Index = ");
                    sb.Append(_codes[offset + 1]);
                    if (_codes[offset + 2] != -1)
                    {
                        sb.Append(", Unindex = ");
                        sb.Append(_codes[offset + 2]);
                    }
                    break;

                case Nullcount:
                case Setcount:
                    sb.Append("Value = ");
                    sb.Append(_codes[offset + 1]);
                    break;

                case Goto:
                case Lazybranch:
                case Branchmark:
                case Lazybranchmark:
                case Branchcount:
                case Lazybranchcount:
                    sb.Append("Addr = ");
                    sb.Append(_codes[offset + 1]);
                    break;
            }

            switch (opcode)
            {
                case Onerep:
                case Notonerep:
                case Oneloop:
                case Notoneloop:
                case Onelazy:
                case Notonelazy:
                case Setrep:
                case Setloop:
                case Setlazy:
                    sb.Append(", Rep = ");
                    if (_codes[offset + 2] == int.MaxValue)
                        sb.Append("inf");
                    else
                        sb.Append(_codes[offset + 2]);
                    break;

                case Branchcount:
                case Lazybranchcount:
                    sb.Append(", Limit = ");
                    if (_codes[offset + 2] == int.MaxValue)
                        sb.Append("inf");
                    else
                        sb.Append(_codes[offset + 2]);
                    break;
            }

            sb.Append(')');

            return sb.ToString();
        }

 public override void DumpState()
 {
     base.DumpState();
     Debug.WriteLine("       " + runcode.OpcodeDescription(runcodepos) +
                     ((runoperator & RegexCode.Back) != 0 ? " Back" : "") +
                     ((runoperator & RegexCode.Back2) != 0 ? " Back2" : ""));
 }