Function merge_choice

src/invent.c:774–810

scan a list of objects to see whether another object will merge with one of them; used in pickup.c when all 52 inventory slots are in use, to figure out whether another object could still be picked up */

   one of them; used in pickup.c when all 52 inventory slots are in use,
   to figure out whether another object could still be picked up */
struct obj *
merge_choice(struct obj *objlist, struct obj *obj)
{
    struct monst *shkp;
    unsigned save_nocharge;

    if (!objlist) /* might be checking 'obj' against empty inventory */
        return (struct obj *) 0;
    if (obj->otyp == SCR_SCARE_MONSTER) /* punt on these */
        return (struct obj *) 0;
    /* if this is an item on the shop floor, the attributes it will
       have when carried are different from what they are now; prevent
       that from eliciting an incorrect result from mergable() */
    save_nocharge = obj->no_charge;
    if (objlist == gi.invent && obj->where == OBJ_FLOOR
        && (shkp = shop_keeper(inside_shop(obj->ox, obj->oy))) != 0) {
        if (obj->no_charge)
            obj->no_charge = 0;
        /* A billable object won't have its `unpaid' bit set, so would
           erroneously seem to be a candidate to merge with a similar
           ordinary object.  That's no good, because once it's really
           picked up, it won't merge after all.  It might merge with
           another unpaid object, but we can't check that here (depends
           too much upon shk's bill) and if it doesn't merge it would
           end up in the '#' overflow inventory slot, so reject it now. */
        else if (inhishop(shkp))
            return (struct obj *) 0;
    }
    do {
        /*assert(objlist != NULL);*/
        if (mergable(objlist, obj))
            break;
        objlist = objlist->nobj;
    } while (objlist);
    obj->no_charge = save_nocharge;
    return objlist;
}

/* merge obj with otmp and delete obj if types agree */
int