#include <grass/gis.h>
#include <grass/raster.h>
/*
 * creates new category and color structures from the patching
 * files category and color files
 *
 * the first patch file is used as the basis. Its cats and colr
 * are read into the final cats/colr structures.
 * Then the other patching layers cats/colr are added to the
 * final cats/colr only if these patching layers actually
 * contributed new categories to the final result
 */

int support(char **names,
	    struct Cell_stats *statf, int nfiles,
	    struct Categories *cats,
	    int *cats_ok,
	    struct Colors *colr, int *colr_ok, RASTER_MAP_TYPE out_type)
{
    int i;
    struct Categories pcats;
    struct Colors pcolr;
    CELL n;
    long count;
    int red, grn, blu;
    int do_cats, do_colr;

    *cats_ok = 1;
    *colr_ok = 1;
    if (Rast_read_cats(names[0], "", cats) < 0)
	*cats_ok = 0;
    G_suppress_warnings(1);
    if (Rast_read_colors(names[0], "", colr) < 0)
	*colr_ok = 0;
    G_suppress_warnings(0);

    if (*cats_ok == 0 && *colr_ok == 0)
	return 0;

    for (i = 1; i < nfiles; i++) {
	do_cats = *cats_ok && (Rast_read_cats(names[i], "", &pcats) >= 0);
	G_suppress_warnings(1);
	do_colr = *colr_ok && (Rast_read_colors(names[i], "", &pcolr) >= 0);
	G_suppress_warnings(0);
	if (!do_cats && !do_colr)
	    continue;
	if (out_type == CELL_TYPE) {
	    Rast_rewind_cell_stats(statf + i);
	    while (Rast_next_cell_stat(&n, &count, statf + i))
		if (n && !Rast_find_cell_stat(n, &count, statf)) {
		    if (do_cats) {
			Rast_update_cell_stats(&n, 1, statf);
			Rast_set_c_cat(&n, &n, Rast_get_c_cat((CELL *) &n, &pcats), cats);
		    }
		    if (do_colr) {
			Rast_get_c_color(&n, &red, &grn, &blu, &pcolr);
			Rast_set_c_color(n, red, grn, blu, colr);
		    }
		}
	}
	else {
	    /* the color would be the color of the first map,
	     * possibly not covering the range of the other maps */
	    *colr_ok = 0;
	}

	if (do_cats)
	    Rast_free_cats(&pcats);
	if (do_colr)
	    /* otherwise this memory is used in colr pointer */
	    Rast_free_colors(&pcolr);
    }
    return 1;
}