#include <stdlib.h>
#include <grass/gis.h>
#include "local_proto.h"

static int ascending(const void *aa, const void *bb)
{
	const DCELL *a = aa, *b = bb;

	if (G_is_d_null_value((DCELL *) a) &&
	    G_is_d_null_value((DCELL *) b))
		return 0;

	if (G_is_d_null_value((DCELL *) a))
		return 1;

	if (G_is_d_null_value((DCELL *) b))
		return -1;

	return (*a < *b) ? -1 : (*a > *b) ? 1 : 0;
}

int sort_cell(DCELL *array, int n)
{
	int i;

	qsort(array, n, sizeof(DCELL), ascending);

	for (i = 0; i < n; i++)
		if (G_is_d_null_value(&array[i]))
			break;

	return i;
}