Function alloc_itermonarr

src/mon.c:4470–4490

manage itermonarr; it used to be allocated and freed every time the monster movement loop ran; now, keep it around most of the time */

/* manage itermonarr; it used to be allocated and freed every time the
   monster movement loop ran; now, keep it around most of the time */
void
alloc_itermonarr(unsigned count)
{
    /* if count is 0 or bigger than itermonsiz or much smaller than
       itermonsiz, release itermonarr (and reset itermonsiz to 0) */
    if (!count || count > itermonsiz || count + 40 < itermonsiz) {
        if (itermonarr)
            free((genericptr_t) itermonarr), itermonarr = NULL;
        itermonsiz = 0;
    }
    /* when count is more than itermonsiz (including when that just
       got reset to 0), allocate a new instance of itermonarr;
       implies that count is greater than 0 */
    if (count > itermonsiz) {
        /* overallocate to reduce free/alloc-again thrashing when the
           number of monsters varies from turn to turn */
        itermonsiz = count + 20;
        itermonarr = (struct monst **) alloc(
                                        itermonsiz * sizeof (struct monst *));
    }
}

/* Iterate all monsters on the level, even dead or off-map ones, calling
   bfunc() for each monster.  If bfunc() returns TRUE, stop iterating.