NRegex.SearchEntry.SaveCntState C# (CSharp) Method

        internal static void SaveCntState(SearchEntry entry, int cntreg, int value)
        {
            entry.isState=true;
            CState current=entry.cCurrent;
            if(current==null) {
                CState head=entry.cHead;
                if(head==null) entry.cHead=entry.cCurrent=current=new CState();
                else current=head;
            } else {
                CState next=current.next;
                if(next==null) {
                    current.next=next=new CState();
                    next.prev=current;
                }
                current=next;
            }
            current.index=cntreg;
            current.value=value;
            entry.cCurrent=current;
        }