#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <string>
#include <cstring>
namespace patternMatch{
using namespace std;
class boyerMoore{
public:
boyerMoore(void):skip(NULL), shift(NULL), charMax(256){}
int bmMake(const string &patternStr){
if( shiftMake(patternStr) < 0 || skipMake(patternStr) < 0)
return -1;
pattern = patternStr;
}
~boyerMoore(void){
bmDesory();
}
const int match(const string &target) const{
if(pattern.empty() || !shift || !skip || target.size() > pattern.size())
return -1;
int targetLen = target.size();
int patternLen = pattern.size();
int i;
int j = 0;
while( j <= targetLen - patternLen){
for(i = patternLen -1; i >= 0 && target[i + j] == pattern[i]; i--);
if(i < 0 )
return j;
else
j = max(shift[i], skip[pattern[i]] - (patternLen - 1 - i));
}
}
virtual void bmDebug(){
cout << "pattern string :" << pattern << endl;
cout << "skip vec :" << endl;
skipDebug();
cout << "shift vec:" << endl;
shiftDebug();
}
private:
int skipMake(const string &patternStr);
/**build assit vec used like kmp*/
void suffixMake(const string &pattern, int *suffix);
int shiftMake(const string &patternStr);
void skipDestory(void) {
if(skip)
delete skip;
}
void shiftDestory(void) {
if(shift)
delete shift;
}
void bmDesory(void){
skipDestory();
shiftDestory();
pattern.clear();
}
virtual void skipDebug(void){
if(skip){
for(int pos = 0; pos < pattern.size(); pos++)
cout << skip[pattern[pos]] << " ";
cout << endl;
}
}
virtual void shiftDebug(void){
if(shift){
for(int pos = 0; pos < pattern.size(); pos++)
cout << shift[pos] << " ";
cout << endl;
}
}
int *skip;
int *shift;
string pattern;
const int charMax;
};
int boyerMoore::skipMake(const string &patternStr){
int pos;
int patternLen = patternStr.size();
skipDestory();
if( NULL == (skip = new int[charMax]))
return -1;
else
memset(skip, 0, charMax);
for(pos = 0; pos < charMax; pos++)
skip[pos] = patternLen;
for(pos = 0; pos <= patternLen - 1; pos++)
skip[(unsigned char)patternStr[pos]] = patternLen - pos - 1;
return 0;
}
void boyerMoore::suffixMake(const string &pattern, int *suffix)
{
int patterLen = pattern.size();
suffix[patterLen - 1] = patterLen;
for(int posMatch = patterLen - 2; posMatch >= 0; posMatch--){
int posCheck = posMatch;
while(posCheck >= 0 && pattern[posCheck] == pattern[patterLen - 1 - (posMatch - posCheck)]){
posCheck--;
}
suffix[posMatch] = posMatch - posCheck;
//cout << posMatch << "-suffix->" << suffix[posMatch] << endl;
}
}
int boyerMoore::shiftMake(const string &patternStr){
int pos;
int patternLen = patternStr.size();
shiftDestory();
if( NULL == (shift = new int[patternLen]))
return -1;
else
memset(shift, 0, sizeof(int) * patternLen);
int *suffix = new int[patternLen];
if(!suffix)
return -1;
else
memset(suffix, 0, sizeof(int) * patternLen);
/** make suffix for shift*/
suffixMake(patternStr, suffix);
for(int pos = 0; pos < patternLen; pos++)
shift[pos] = patternLen;
int posMark = 0;
for(int pos = patternLen - 1; pos >= 0; pos--){
if(suffix[pos] == pos + 1){
int posVal = patternLen - pos - 1;
for(; posMark < posVal; posMark++)
if( patternLen == shift[posMark]){
shift[posMark] = posVal;
//cout << posMark << "->" << shift[posMark] << endl;
}
}
}
for(int pos = 0; pos < patternLen -1; pos++)
shift[patternLen - suffix[pos] - 1] = patternLen - pos -1;
if(suffix)
delete suffix;
return 0;
}
}
using namespace std;
using namespace patternMatch;
int main()
{
string pattern, target;
class boyerMoore bm;
cout << "intput pattern match string" << endl;
cin >> pattern;
if(bm.bmMake(pattern) < 0){
cout << "Init pattern string fail" << endl;
return -1;
}
bm.bmDebug();
cout << "intput target string" << endl;
return 0;
}
参考文章
http://en.wikipedia.org/wiki/Boyer%E2%80%93Moore_string_search_algorithm
http://wenku.baidu.com/link?url=-GK6uL1f_nvlHtZ3KNXfY_9ydgOTijIXoIapJBweNISBW_pZIvKKS6sshbpELw99VumsxKgxXYur8qRSHxvuN7ub5OiSXY9yPAOEm63NMju###
IN BUILDING
来源:oschina
链接:https://my.oschina.net/u/572632/blog/291100