KMP字符串匹配

#ifndef _MSTRING_H
#define _MSTRING_H

#include<iostream>
#include<string.h>
using namespace std;

#define MSTRING_ERROR 1
#define MSTRING_NORMAL 0

class MString
{
public:
	MString();
	MString(char *str);
	~MString();
	void println();
	int get_lenth();
	MString &operator=(char *str);  //等号赋值
	MString &operator=(MString T);
	void add_tail(const char *str); //向尾部连接字符串
	void add_tail(MString mstr);
	void add_ahead(const char *str);  //向头部连接字符串
	void add_ahead(MString mstr);
	int find_first_of(const char *str);  //查找第一个匹配字符串位置
	int find_first_of(MString mstr);
	int find_all_of(const char *str,int *out,int maxnum);  //找到所有匹配字符串位置，最大数目maxnum,返回个数，out数组
	int find_all_of(MString mstr, int *out, int maxnum);
	char* get_char();  //返回字符指针，原指针非复制，因此谨慎赋值
	int replace_all(const char *straim, const char *strtar); //替换全部straim字符串为strtar
	int replace_all(MString mstraim, MString mstrtar);
	int cmp(const char *str); //比较大小
	int cmp(MString mstr);

private:
	void get_next(const char *T, int *next);
	int kmp(const char *S,const char *T, int pos);
private:
	char *ch;
	int lenth;
};

MString::MString()
{
	lenth = 0;
	ch = NULL;
}

MString::MString(char *str)
{
	lenth = strlen(str);
	ch = new char[lenth+1];
	strcpy(ch, str);
}

MString::~MString()
{
	if (ch != NULL)
	{
		delete[] ch;
	}
}

void MString::println()
{
	printf("%s\n", ch);
}

int MString::get_lenth()
{
	return lenth;
}

inline MString & MString::operator=(char * str)
{
	if (ch != NULL)
	{
		delete[] ch;
	}
	lenth = strlen(str);
	ch = new char[lenth+1];
	strcpy(ch, str);
	return *this;
}

inline MString & MString::operator=(MString T)
{
	if (ch != NULL)
	{
		delete[] ch;
	}
	lenth = T.lenth;
	ch = new char[lenth + 1];
	strcpy(ch, T.ch);
	return *this;
}

void MString::add_tail(const char * str)
{
	char *tmpstr;
	int len, i, g;
	tmpstr = new char[lenth+1];
	strcpy(tmpstr, ch);
	if (ch != NULL)
	{
		delete[] ch;
	}
	len = strlen(str);
	ch = new char[len + lenth + 1];
	g = 0;
	for (i = 0;i < lenth;i++)
	{
		ch[g++] = tmpstr[i];
	}
	for (i = 0;i < len;i++)
	{
		ch[g++] = str[i];
	}
	ch[g] = '\0';
	lenth = len + lenth;
	delete[] tmpstr;
}

inline void MString::add_tail(MString mstr)
{
	add_tail(mstr.ch);
}

void MString::add_ahead(const char *str)
{
	char *tmpstr;
	int len, i, g;
	tmpstr = new char[lenth + 1];
	strcpy(tmpstr, ch);
	if (ch != NULL)
	{
		delete[] ch;
	}
	len = strlen(str);
	ch = new char[len + lenth + 1];
	g = 0;
	for (i = 0;i < len;i++)
	{
		ch[g++] = str[i];
	}
	for (i = 0;i < lenth;i++)
	{
		ch[g++] = tmpstr[i];
	}
	ch[g] = '\0';
	lenth = len + lenth;
	delete[] tmpstr;
}

inline void MString::add_ahead(MString mstr)
{
	add_ahead(mstr.ch);
}

void MString::get_next(const char *T, int *next)
{
	char *tmpstr;
	int len;
	len = strlen(T);
	tmpstr = new char[len + 2];
	strcpy(tmpstr + 1, T);
	tmpstr[0] = '\0';
	int i, j;
	i = 1;next[1] = 0;j = 0;
	while (i<len)
	{
		if (j == 0 || tmpstr[i] == tmpstr[j])
		{
			++i;++j;
			if (tmpstr[i] != tmpstr[j]) next[i] = j;
			else next[i] = next[j];
		}
		else j = next[j];
	}
	delete[] tmpstr;
}

//返回第一个T出现在S处的下标,pos设定从哪个下标开始向后找
int MString::kmp(const char *S,const char *T, int pos)
{
	int i, j, lens, lent, k;
	int *next;
	i = pos;j = 0;
	lens = strlen(S);
	lent = strlen(T);
	next = new int[lent + 1];
	get_next(T, next);
	k = 0;
	while (i<lens&&j<lent)
	{
		if (S[i] == T[j])
		{
			i++;
			j++;
		}
		else
		{
			j = next[j + 1] - 1;
			if (j == -1)
			{
				i++;
				j++;
			}
		}
	}
	delete[] next;
	if (j >= lent) return i - lent;
	else return -1;
}

/*
搜索查找第一个匹配字符的位置,查找算法:KMP
*/
int MString::find_first_of(const char *str)
{
	if (ch == NULL) return -1;
	return kmp(ch,str,0);
}

inline int MString::find_first_of(MString mstr)
{
	return find_first_of(mstr.ch);
}

int MString::find_all_of(const char *str,int *out,int maxnum)
{
	if (ch == NULL) return -1;
	if (maxnum < 1) return -1;
	int i,j,len,num;
	len = strlen(str);
	i = 0;
	j = 0;
	num = 0;
	while (1)
	{
		out[i] = kmp(ch, str, j);
		if (out[i] == -1) return i;
		j = len+ out[i];
		i++;
		if (i >= maxnum) return maxnum;
	}
}

inline int MString::find_all_of(MString mstr, int * out, int maxnum)
{
	return find_all_of(mstr.ch, out, maxnum);
}

inline char * MString::get_char()
{
	return ch;
}

int MString::replace_all(const char *straim, const char *strtar)
{
	int i, j, num, lena, lent, lenc;
	j = 0;
	num = 0;
	lena = strlen(straim);
	lent = strlen(strtar);
	lenc = strlen(ch);
	while (1)
	{
		i = kmp(ch, straim, j);
		if (i == -1) break;
		num++;
		j = i + lena;
	}
	int *ta;
	ta = new int[num];
	j = 0;
	i = 0;
	for (i = 0;i < num;i++)
	{
		ta[i] = kmp(ch, straim, j);
		j = ta[i] + lena;
	}
	char *distr;
	int lendi;
	lendi = lenc - lena*num + lent*num + 1;
	distr = new char[lendi];
	i = 0;
	int g = 0;
	int k = 0;
	while (i<lendi-1)
	{
		if (k != ta[g])
		{
			distr[i++] = ch[k++];
		}
		else
		{
			for (j = 0;j < lent;j++)
			{
				distr[i++] = strtar[j];
			}
			g++;
			k += lena;
		}
	}
	distr[lendi - 1] = '\0';
	lenth = lendi - 1;
	delete[] ta;
	if (ch != NULL) delete[] ch;
	ch = distr;
	return num;
}

inline int MString::replace_all(MString mstraim, MString mstrtar)
{
	return replace_all(mstraim.ch, mstrtar.ch);
}

inline int MString::cmp(const char * str)
{
	return strcmp(ch, str);
}

inline int MString::cmp(MString mstr)
{
	return strcmp(ch, mstr.ch);
}

#endif