[GRASS-dev] Re: bug in Vect_cidx_find_next() ?

[Moritz Lennert]

Radim,

> Radim Blazek wrote:
>> To simplify use of cat index in modules I would suggest 2 new functions
>> (not tested/compiled):
>>
>> void Vect_cidx_find_lines ( struct Map_info *Map, int layer, int cat,
>>                                 struct ilist *lines )
>> {
>>      int type, line;
>>      struct Cat_index *ci;
>>
>>      Vect_reset_list ( lines );
>>      int field_index = Vect_cidx_get_field_index ( Map, layer );
>>      ci = &(Map->plus.cidx[field_index]);
>>
>>      int idx = Vect_cidx_find_next ( Map, field_index, cat, 0,
>>                                  GV_LINES|GV_POINTS, &type, &line );

This should be

int idx = Vect_cidx_find_next ( Map, field_index, cat, GV_LINES|GV_POINTS,
                               0,&type, &line );


>>
>>      if ( idx == -1 ) return;
>>
>>      do {
>>          if ( !(ci->cat[idx][1] & GV_LINES|GV_POINTS)
>>               ||  ci->cat[idx][0]  != cat )
>
>
> Again, if Vect_cidx_find_next works correctly, how could this happen ?
> If it does this would be a bug in Vect_cidx_find_next, or ?

I understand now that this question was nonsense, please forget.

>
>>          {
>>               break;
>>           }
>>           Vect_list_append ( lines, ci->cat[idx][2] );
>>           idx++;
>>       } while (   idx < ci->n_cats );
>>       return;
>> }
>>

I have tested above function and it seems to work well. Helps simplifying
my code...

>> and similarly Vect_cidx_find_areas

Would this similar function look like below ? If yes, why make this into a
separate function and not simply add a 'type' parameter to above function
which we could then call Vect_cidx_find_ojects_by_cat or something like
that ?


***proposal for Vect_cidx_find_areas**********

void Vect_cidx_find_areas ( struct Map_info *Map, int layer, int cat,
                                 struct ilist *areas )
{
      int type, line;
      struct Cat_index *ci;

      Vect_reset_list ( areas );
      int field_index = Vect_cidx_get_field_index ( Map, layer );
      ci = &(Map->plus.cidx[field_index]);

      int idx = Vect_cidx_find_next ( Map, field_index, cat,
                                  GV_AREA, 0, &type, &line );

      if ( idx == -1 )
       {
        return;
       }

      do {
          if ( !(ci->cat[idx][1] & GV_AREA)
               ||  ci->cat[idx][0]  != cat )
          {
               break;
           }
           Vect_list_append ( areas, ci->cat[idx][2] );
           idx++;
       } while (   idx < ci->n_cats );
       return;
}

Moritz