calcdb.cc

charm是基于垂直数据集挖掘关联规则的一个著名算法

#include <string>
#include "calcdb.h"

int *Dbase_Ctrl_Blk::freqidx = NULL;
Array<int> **Dbase_Ctrl_Blk::tidlists = NULL;
int *Dbase_Ctrl_Blk::tidbuf = NULL;
int Dbase_Ctrl_Blk::tidbuflen = 0;

Dbase_Ctrl_Blk::Dbase_Ctrl_Blk(char *infile, int buf_sz)
{
   fd = open (infile, O_RDONLY);
   if (fd < 0){
      printf("ERROR: InvalidFile -- Dbase_Ctrl_Blk()\n");
      exit(-1);
   }
   buf_size = buf_sz;
   buf = new int [buf_sz];
   cur_buf_pos = 0;
   cur_blk_size = 0;
   readall = 0;
   endpos = lseek(fd,0,SEEK_END);
}
   
Dbase_Ctrl_Blk::~Dbase_Ctrl_Blk()
{
   delete [] buf;
   close(fd);
}

void Dbase_Ctrl_Blk::get_next_trans_ext()
{
   // Need to get more items from file
   int res = cur_blk_size - cur_buf_pos;
   if (res > 0)
   {
      // First copy partial transaction to beginning of buffer
      memcpy((void *)buf,
             (void *)(buf + cur_buf_pos),
             res * ITSZ);
      cur_blk_size = res;
   }
   else
   {
      // No partial transaction in buffer
      cur_blk_size = 0;
   }

   res = read(fd, (void *)(buf + cur_blk_size),
              ((buf_size - cur_blk_size)*ITSZ));
   
   if (res < 0){
      perror("reading in database");
      exit(errno);
   }
   cur_blk_size += res/ITSZ;
   //if (cur_blk_size > 0)
   //{
   //   custid = buf[0];
   //   tid = buf[1];
   //   numitem = buf[2];
   //   cur_buf_pos = 3;   
   //}
   cur_buf_pos = 0;
}