Ejemplo n.º 1
0
        /// <summary>
        /// 用NFA构造DFA
        /// </summary>
        /// <param name="nfa"></param>
        private void CreateDFA(NFA nfa)
        {
            Stack <DFAStateNode> stack = new Stack <DFAStateNode>();

            startStateNode = new DFAStateNode();
            startStateNode.AddNFAStateNodeList(NullClosure(nfa.StartStateNode));
            allStateNodes.Add(startStateNode);

            stack.Push(startStateNode);

            while (stack.Count != 0)
            {
                DFAStateNode curNode = stack.Pop();

                foreach (char c in nfa.Alphabet)
                {
                    List <NFAStateNode> destNodes = NullClosure(MoveTo(curNode, c));

                    // 是否需要产生新的DFA状态节点
                    bool needNew = true;

                    foreach (DFAStateNode existedNode in allStateNodes)
                    {
                        if (existedNode.Contains(destNodes))
                        {
                            curNode.Connect(existedNode, c);
                            needNew = false;
                            break;
                        }
                    }

                    if (needNew && destNodes.Count != 0)
                    {
                        DFAStateNode newNode = new DFAStateNode();
                        newNode.AddNFAStateNodeList(destNodes);
                        curNode.Connect(newNode, c);
                        stack.Push(newNode);
                        allStateNodes.Add(newNode);
                    }
                }
            }

            FillEndStateNodes();
        }