int find_first_step(sh_int src, sh_int target, int stay_zone)
{
int curr_dir;
sh_int curr_room;
int src_zone = ((src - (src % 100)) / 100);
int target_zone = ((target - (target % 100)) / 100);
if (src < 0 || src > top_of_world || target < 0 || target > top_of_world) {
stderr_log("Illegal value passed to find_first_step (graph.c)");
return BFS_ERROR;
}
/* dez 19980805
if ((src_zone != target_zone && stay_zone == 1) || stay_zone == 2) {
return BFS_NO_PATH;
}
*/
if (src_zone != target_zone && stay_zone == 1) {
return BFS_NO_PATH;
}
if (src == target) {
return BFS_ALREADY_THERE;
}
/* clear marks first */
for (curr_room = 0; curr_room <= top_of_world; curr_room++) {
UNMARK(curr_room);
}
MARK(src);
/* first, enqueue the first steps, saving which direction we're going. */
for (curr_dir = 0; curr_dir < NUM_OF_DIRS; curr_dir++) {
if (VALID_EDGE(src, curr_dir)) {
MARK(TOROOM(src, curr_dir));
bfs_enqueue(TOROOM(src, curr_dir), curr_dir);
}
}
/* now, do the classic BFS. */
while (queue_head) {
if (queue_head->room == target) {
curr_dir = queue_head->dir;
bfs_clear_queue();
return curr_dir;
} else {
for (curr_dir = 0; curr_dir < NUM_OF_DIRS; curr_dir++) {
if (VALID_EDGE(queue_head->room, curr_dir)) {
MARK(TOROOM(queue_head->room, curr_dir));
bfs_enqueue(TOROOM(queue_head->room, curr_dir), queue_head->dir);
}
}
bfs_dequeue();
}
}
return BFS_NO_PATH;
}
/*
* find_first_step: given a source room and a target room, find the first
* step on the shortest path from the source to the target.
*
* Intended usage: in mobile_activity, give a mob a dir to go if they're
* tracking another mob or a PC. Or, a 'track' skill for PCs.
*/
int find_first_step(room_rnum src, room_rnum target)
{
int curr_dir;
room_rnum curr_room;
if (src == NOWHERE || target == NOWHERE || src > top_of_world || target > top_of_world) {
extended_mudlog(NRM, SYSL_BUGS, TRUE, "Illegal value %d or %d passed to find_first_step. (%s)", src, target, __FILE__);
return (BFS_ERROR);
}
if (src == target)
return (BFS_ALREADY_THERE);
/* clear marks first, some OLC systems will save the mark. */
for (curr_room = 0; curr_room <= top_of_world; curr_room++)
UNMARK(curr_room);
MARK(src);
/* first, enqueue the first steps, saving which direction we're going. */
for (curr_dir = 0; curr_dir < NUM_OF_DIRS; curr_dir++)
if (VALID_EDGE(src, curr_dir)) {
MARK(TOROOM(src, curr_dir));
bfs_enqueue(TOROOM(src, curr_dir), curr_dir);
}
/* now, do the classic BFS. */
while (queue_head) {
if (queue_head->room == target) {
curr_dir = queue_head->dir;
bfs_clear_queue();
return (curr_dir);
} else {
for (curr_dir = 0; curr_dir < NUM_OF_DIRS; curr_dir++)
if (VALID_EDGE(queue_head->room, curr_dir)) {
MARK(TOROOM(queue_head->room, curr_dir));
bfs_enqueue(TOROOM(queue_head->room, curr_dir), queue_head->dir);
}
bfs_dequeue();
}
}
return (BFS_NO_PATH);
}
void bfs_clear_queue(void)
{
while (queue_head)
bfs_dequeue();
}
int find_first_step( ROOM_INDEX_DATA * src, ROOM_INDEX_DATA * target, int maxdist )
{
int curr_dir, count;
EXIT_DATA *pexit;
if( !src || !target )
{
bug( "%s", "Illegal value passed to find_first_step (track.c)" );
return BFS_ERROR;
}
if( src == target )
return BFS_ALREADY_THERE;
if( src->area != target->area )
return BFS_NO_PATH;
room_enqueue( src );
MARK( src );
/*
* first, enqueue the first steps, saving which direction we're going.
*/
for( pexit = src->first_exit; pexit; pexit = pexit->next )
if( valid_edge( pexit ) )
{
curr_dir = pexit->vdir;
MARK( pexit->to_room );
room_enqueue( pexit->to_room );
bfs_enqueue( pexit->to_room, curr_dir );
}
count = 0;
while( queue_head )
{
if( ++count > maxdist )
{
bfs_clear_queue( );
clean_room_queue( );
return BFS_NO_PATH;
}
if( queue_head->room == target )
{
curr_dir = queue_head->dir;
bfs_clear_queue( );
clean_room_queue( );
return curr_dir;
}
else
{
for( pexit = queue_head->room->first_exit; pexit; pexit = pexit->next )
if( valid_edge( pexit ) )
{
curr_dir = pexit->vdir;
MARK( pexit->to_room );
room_enqueue( pexit->to_room );
bfs_enqueue( pexit->to_room, queue_head->dir );
}
bfs_dequeue( );
}
}
clean_room_queue( );
return BFS_NO_PATH;
}
