re.h

输入一个正则表达式

#ifndef _REGULAR_EXP_H_
#define	_REGULAR_EXP_H_

#include <memory.h>

#include <set>
#include <string>
#include <algorithm>

#include "NFA.h"
#include "DFA.h"
#define MAP_SIZE	('z' - '0' + 1)

using namespace std;

class Scanner
{
private:
	// Regular expression string
	string	re;
	int		off;

	// Analyse the string, then we can know how many characters are used.
	void analyze();

public:
	// token type
	enum {CHARS, SYMBOL, SCAN_ERR, ENDSTRING};

	// Map character to sequence number
	int		rawMap[MAP_SIZE];

	// Map charset sequence number to character
	int		*map;
	int		mapSize;
	
	int		token;
	int		value;
	Scanner()
	{
		off = 0;
		mapSize = 0;
		map = NULL;
		memset(rawMap, 0, MAP_SIZE * sizeof(int));
	}
	~Scanner()
	{
		delete []map; map = NULL;
	}
	void setRe(const char *_re)
	{
		re = _re;
		analyze();
	}
	// String scanner
	void get();
};

class RegularExp
{
private:
	Scanner scanner;
	// Recursive expression parser
	NFA *unionSet();
	NFA *intersectionSet();
	NFA *join();
	NFA *complementSet();
	NFA *closure();
	NFA *element();
protected:
	int	error(const char *msg);
public:
	NFA	*nfa;
	DFA *dfa;

	// Constructions
	RegularExp() 
	{ 
		nfa = NULL;
		dfa = NULL; 
	}
	~RegularExp()
	{
		delete nfa;
		delete dfa;
	}
	// Parse the regular expression into NFA
	void parse(const char *_re) 
	{ 
		scanner.setRe(_re);
		parse();
	}
	void parse(void);
	void buildDFA()
	{
		if(dfa != NULL) 
		{
			delete dfa;
		}
		dfa = new DFA(nfa, scanner.rawMap);
	}
	int	identify(const char *str)
	{
		return dfa->identify(str);
	}
};

#endif //_REGULAR_EXP_H_