Sunday串匹配算法 C语言实现

 unsigned char * sunday( void * a_buf1,
                         unsigned int len1,
                         void * a_buf2,
                         unsigned int len2 ){

     unsigned char * buf1 = ( unsigned char * )a_buf1;
     unsigned char * buf2 = ( unsigned char * )a_buf2;

     unsigned int next[];
     unsigned int i, j, pos;

     for( i = ; i < ; ++i ){

         next[i] = len2 + ;
     }

     for( i = ; i < len2; ++i ){

         next[buf2[i]] = len2 - i;
     }

     pos = ;

     while( pos < len1 - len2 +  ){

         i = pos;
         j = ;

         while( j < len2 ){

             if( buf1[i] != buf2[j] ){

                 pos += next[buf1[pos + len2]];
                 break;
             }

             ++i;
             ++j;
         }

         if( j == len2 ){

             return &buf1[pos];
         }
     }

     return NULL;
 }                    

和KMP一样，在查询小串的时候都不如优化过的库函数strstr。