#include <grass/gis.h>
/*
 * patch in non-zero data over zero data
 * keep track of the categories which are patched in
 * for later use in constructing the new category and color files
 *
 * returns: 1 the result still contains nulls
 *          0 the result contains no zero nulls
 */

int G_is_zero_value(
    void *rast,
    RASTER_MAP_TYPE data_type)
{
 
 /* insert 0 check here */

  return G_is_null_value(rast, data_type) ||
         G_get_raster_value_d(rast, data_type) != 0.0 ? 0 : 1;
}


int do_patch (
    void *result,void *patch,
    struct Cell_stats *statf,int ncols,
    RASTER_MAP_TYPE out_type,
    int ZEROFLAG)
{
  int more;

  more = 0;
  while (ncols-- > 0)
  {
    if (ZEROFLAG)  /* use 0 for transparency instead of NULL */
    {
	if (G_is_zero_value(result, out_type) ||
	    G_is_null_value(result, out_type))
	{
	    /* Don't patch hole with a null, just mark as more */
	    if(G_is_null_value(patch, out_type))
		more = 1;
            else
	    {
	        /* Mark that there is more to be done if we patch with 0 */
	        if(G_is_zero_value(patch, out_type))
	            more = 1;
	        G_raster_cpy(result, patch, 1, out_type);
		if(out_type==CELL_TYPE)
	            G_update_cell_stats ((CELL *) result, 1, statf);
	    }
	} /* ZERO support */
    }
    
    else            /* use NULL for transparency instead of 0 */
    {
	if (G_is_null_value(result, out_type))
	{
	    if(G_is_null_value(patch, out_type))
		more = 1;
            else
	    {
	        G_raster_cpy(result, patch, 1, out_type);
		if(out_type==CELL_TYPE)
	            G_update_cell_stats ((CELL *) result, 1, statf);
	    }
       	} /* NULL support */
     }  	
     result = G_incr_void_ptr(result, G_raster_size(out_type));
     patch = G_incr_void_ptr(patch, G_raster_size(out_type));
  }
  return more;
}