biodemo.c

void pack_double(struct db *database, double d[], int n)
{
  int len = sizeof(double) * n;
  struct db_node *node = new_node(len);
  memcpy(node->data, d, len);
  dump(database, node);
}

int unpack_double(struct db *database, double d[], int n, int idx)
{
  int code = -1;
  int len = sizeof(double) * n;
  
  if (idx > -1)
  {
     struct db_node *node = undump(database, idx);
     if (node != NULL)
     {
	memcpy(d, node->data, len);
	code = 0;
     }
  }
  return code;
}

// write database
int main(int argc, char *argv[])
{

  int magic = 123;
  struct db *database = createdb(magic, "lastest.d", sizeof(double)*5);
  double d[5] = {2,3,4,5,1};
  double s[5] = {1,2,3,4,5};
  pack_double(database, d, 5);
  pack_double(database, s, 5);

  writedb(database);
  
  return 0;
}

// open and use database
int main(int argc ,char *argv[])
{

  struct db * database = opendb("lastest.d");
  double d[5];
  if(unpack_double(database, d, 5, 1))
  {
	  printf("invalid index!\n");
  }
  else
  for(int i = 0; i < 5; ++i)
	  printf("%lf\n", d[i]);

  closedb(database);

  getchar();
  return 0;
}