/* Print a check if the cell was visited. */
void maze_to_fig_visited(FILE *fp, struct maze *mp, int row, int col, int upc)
{
if (maze_get_cell(mp, row, col) & VISITED)
maze_to_fig_line(fp, col * upc, row * upc,
(col + 1) * upc, (row + 1) * upc, 14,
100 + maze_get_cell_tid(mp, row, col));
}
/*
* Mark the subsolution located by a interior thread, in other words, a
* thread other than the ones that started at the beginning and end cells.
*/
int maze_mark_subsolution(struct maze *mp, int r1, int c1, int r2, int c2)
{
int cr1 = r1;
int cc1 = c1;
int cr2 = r2;
int cc2 = c2;
cell_t *cp;
int d1 = maze_get_cell_distance(mp, cr1, cc1);
int d2 = maze_get_cell_distance(mp, cr2, cc2);
int nr;
int nc;
int s = 0;
for (;;) {
if (maze_get_cell_tid(mp, cr1, cc1) !=
maze_get_cell_tid(mp, cr2, cc2))
ABORT();
if (cr1 == cr2 && cc1 == cc2) {
cp = maze_get_cell_addr(mp, cr1, cc1);
*cp |= SOLUTION;
return s + 1;
}
if (d1 > d2) {
maze_mark_advance_cell(mp, cr1, cc1, &nr, &nc);
s++;
cr1 = nr;
cc1 = nc;
d1 = maze_get_cell_distance(mp, cr1, cc1);
} else if (d1 <= d2 && d2 != 1) {
maze_mark_advance_cell(mp, cr2, cc2, &nr, &nc);
s++;
cr2 = nr;
cc2 = nc;
d2 = maze_get_cell_distance(mp, cr2, cc2);
} else
ABORT();
}
}
/* Record an encounter between a pair of threads. */
void record_encounter(struct maze *mp, int cr, int cc, int tr, int tc)
{
int theirtid;
struct maze_child_shared *mcsp;
if (mymcp == NULL || nthreads == 1)
return; /* Not yet solving the maze or only one thread. */
mcsp = mymcp->mcsp;
theirtid = maze_get_cell_tid(mp, tr, tc);
if (theirtid == myid)
return; /* We ran into ourselves, so ignore. */
(void)__sync_lock_test_and_set(&mymcp->adj[theirtid].mr, cr);
mymcp->adj[theirtid].mc = cc;
mymcp->adj[theirtid].tr = tr;
mymcp->adj[theirtid].tc = tc;
if (nthreads == 2)
ACCESS_ONCE(mcsp->done) = 1;
maze_solve_propagate(mymcp, &mymcp->mcp0[theirtid]);
maze_solve_propagate(&mymcp->mcp0[theirtid], mymcp);
}
/* Return true if both cells were visited by the same thread. */
int maze_same_tids(struct maze *mp, int r1, int c1, int r2, int c2)
{
return maze_get_cell_tid(mp, r1, c1) == maze_get_cell_tid(mp, r2, c2);
}
