/// <summary>
/// 获取开始和结束节点
/// </summary>
/// <returns>开始和结束节点组成的数组</returns>
public int[] GetStartEndNode()
{
int[] StartEndNode = new int[2];
NFAM nfa1 = (NFAM)StartEndStatesStack.Pop();
StartEndNode[0] = nfa1.startstatus;
StartEndNode[1] = nfa1.endstatus;
return(StartEndNode);
}
/// <summary>
/// 根据查表得到的优先级构造相应的状态
/// </summary>
/// <param name="compare">优先级关系</param>
/// <param name="str">正规式字符串</param>
private void Construction(char compare, string str)
{
switch (compare)
{
case '<':
SignStack.Push(ch);
if (index < str.Length - 1)
{
index++;
}
break;
case '>':
switch (SignStack.Pop())
{
case '.':
NFAM nfa2 = (NFAM)StartEndStatesStack.Pop();
NFAM nfa3 = (NFAM)StartEndStatesStack.Pop();
NFAM nfa4 = new NFAM(nfa3.endstatus, nfa2.startstatus, 'ε');
NfamQueue.Enqueue(nfa4);
NFAM nfa5 = new NFAM(nfa3.startstatus, nfa2.endstatus, '#');
StartEndStatesStack.Push(nfa5);
break;
case '|':
NFAM nfa6 = (NFAM)StartEndStatesStack.Pop();
NFAM nfa7 = (NFAM)StartEndStatesStack.Pop();
//构造或运算剩下的4条弧
NFAM nfa8 = new NFAM(nfa6.endstatus + 1, nfa7.startstatus, 'ε');
NFAM nfa9 = new NFAM(nfa6.endstatus + 1, nfa6.startstatus, 'ε');
NFAM nfa10 = new NFAM(nfa7.endstatus, nfa6.endstatus + 2, 'ε');
NFAM nfa11 = new NFAM(nfa6.endstatus, nfa6.endstatus + 2, 'ε');
//新构造的弧入队列
NfamQueue.Enqueue(nfa8);
NfamQueue.Enqueue(nfa9);
NfamQueue.Enqueue(nfa10);
NfamQueue.Enqueue(nfa11);
NFAM nfa12 = new NFAM(nfa6.endstatus + 1, nfa6.endstatus + 2, '#');
//起始节点入栈
StartEndStatesStack.Push(nfa12);
break;
}
break;
case '=':
SignStack.Pop();
if (index < str.Length - 1)
{
index++;
}
break;
}
}
/// <summary>
/// 分析正规式并构造相应的NFAM
/// </summary>
/// <param name="str">输入一个正规式</param>
/// <returns>构造的NFA</returns>
private Queue <NFAM> AnalyseRegex(string str)
{
str += "#";
ch = str[index];
int start = 0;
int end = 1;
char compare = '=';
int m = 0;
int n = 0;
do
{
ch = str[index];
if (Char.IsLetterOrDigit(ch))
{
if (StartEndStatesStack.Count == 0)
{
NFAM nfa = new NFAM(start, end, ch);
StartEndStatesStack.Push(nfa); //入状态栈
NfamQueue.Enqueue(nfa); //入队列
}
else
{
end = ((NFAM)StartEndStatesStack.Peek()).endstatus;
NFAM nfa = new NFAM(end + 1, end + 2, ch);
StartEndStatesStack.Push(nfa); //入状态栈
NfamQueue.Enqueue(nfa); //弧入队列
}
if (index < str.Length - 1)
{
index++;
}
}
else if (str[index] == '*')
{
NFAM nfa13 = (NFAM)StartEndStatesStack.Pop();
//构造4条空弧
NFAM nfa14 = new NFAM(nfa13.endstatus, nfa13.startstatus, 'ε');
NFAM nfa15 = new NFAM(nfa13.endstatus + 1, nfa13.startstatus, 'ε');
NFAM nfa16 = new NFAM(nfa13.endstatus, nfa13.endstatus + 2, 'ε');
NFAM nfa17 = new NFAM(nfa13.endstatus + 1, nfa13.endstatus + 2, 'ε');
NFAM nfa18 = new NFAM(nfa13.endstatus + 1, nfa13.endstatus + 2, '#');
//新弧入栈
NfamQueue.Enqueue(nfa14);
NfamQueue.Enqueue(nfa15);
NfamQueue.Enqueue(nfa16);
NfamQueue.Enqueue(nfa17);
//起始节点入队列
StartEndStatesStack.Push(nfa18);
if (index < str.Length - 1)
{
index++;
}
}
else
{
#region //查表
for (int i = 0; i < 6; i++) //i
{
if (SignStack.Peek() == TableOfPriority[i, 0])
{
m = i;
break;
}
}
for (int j = 0; j < 6; j++)//i+1
{
if (str[index] == TableOfPriority[0, j])
{
n = j;
break;
}
}
#endregion
compare = TableOfPriority[m, n];
Construction(compare, str);
}
}while (SignStack.Peek() != '#' || str[index] != '#');
return(NfamQueue);
}
