how to write binary data into BAT tail?

28 Jun 2013

      i want to create a monetdb function to help write my astronomical
*binary*processing result into database,this function will load the
binary result
from memory directly into monetdb to save time,  so i defined a UDF
binaryCopy() ,

 svom.c

int binaryCopy(str columnname, str buffer, int count)
{
    mvc *sql = NULL;
    sql_table *tmatch = NULL;
   /*BATs in which the data of the columns of the output table will be
stored*/
   BAT *tmatch_column = NULL;
   BUN nr_rows;
   /* pointer to the tail of above BAT, which is just a normal C-array */
   lng *tmatch_column_lng_t = NULL;
   flt *tmatch_column_flt_t = NULL;

   /*_bind_table is just a wrapper that tries to see if it can find the
table
    match_table under three default schemas*/
   if(!(tmatch = _bind_table(sql, NULL, "testtable")))
       //return sql_message("42S02!BINARYLOAD():no such table test");
       return 0;

   //nr_match = 20000;
   nr_rows = count;
/*
 create BATs for all columns of the output table 'tmatch'
*/
   if(strcmp(columnname,"starid")==0 || strcmp(columnname,"crossid")==0
||strcmp(columnname,"catid")==0 ) {
        tmatch_column = BATnew(TYPE_void, TYPE_lng,nr_rows);
   }else {
        tmatch_column = BATnew(TYPE_void,TYPE_flt,nr_rows);
   }

/*
 now tmatch_starid_t points to the first element of the BAT's tails
*/
   tmatch_column_lng_t = (lng*)Tloc(tmatch_column,BUNfirst(tmatch_column));

/*
    now we can write data into the BAT tail
*/
   if((strcmp(columnname,"starid")==0) || (strcmp(columnname,"crossid")==0)
||(strcmp(columnname,"catid")==0) ) {
        *memcpy(tmatch_column_lng_t,buffer,nr_rows*sizeof(lng));  //is it
right to write binary data into BAT???*
   }else {
       memcpy(tmatch_column_flt_t, buffer, nr_rows*sizeof(flt));
   }

   /* Set proper properties for all BATs */
   BATsetcount(tmatch_column,nr_rows);

   BATseqbase(tmatch_column,0);

/*
    sorted:1, column is sorted in ascending order
*/
   tmatch_column->tsorted = 0;

/*
 if the tail is reverse sorted.
*/
   tmatch_column->trevsorted = 0;

/*
 if the tail contains NIL values
*/
   tmatch_column->T->nil = 0;

/*
if the tail doesn't contain NIL values
*/
   tmatch_column->T->nonil = 0;

/*
if the values in the tail are unique.Since BATkey only works with BAT heads,
 * BATmirror is used to switch the head and tail of the BATs
*/
   if(strcmp(columnname,"starid")==0) {
       BATkey(BATmirror(tmatch_column),1); //only starid is 1
   }else {
   BATkey(BATmirror(tmatch_column),0);
   }

/*
finally, append the result BATs to the result table
 * ignore errors, since we are finishing
*/
   _append_bat(sql,tmatch,columnname,tmatch_column);

   /*
 The BATs now contain the data for the columns of the output tables,
 * append_bat registers in the system where to find the BAT for those
columns.
*/

/*
 To avoid memory leak, BAT reference counter must be decreased after use.
 * That can be done using BBPunfix.
*/
   if(tmatch_column) BBPunfix(tmatch_column->batCacheid);

   return 1; //success
}

Thanks!

how to write binary data into BAT tail?

hlfwm hlfwm