/**
* Given the current selected Company slot and a direction to search,
* get the first free Company slot or INVALID_COMPANY if there's none.
* @param slot The currently selected Company slot
* @param dir The direction to search (-1 to search above, +1 to search below)
* @return the first free CompanyID that is found from the given direction
* @note returns INVALID_COMPANY if none was found.
*/
static CompanyID GetFreeSlot(CompanyID slot, int dir = 0)
{
assert(dir == -1 || dir == +1);
if (dir == -1) {
slot--;
for (slot; slot >= COMPANY_FIRST; slot--) {
if (IsConsideredDead(slot)) return slot;
}
} else {
if (dir == +1) {
slot++;
for (slot; slot < MAX_COMPANIES; slot++) {
if (IsConsideredDead(slot)) return slot;
}
}
}
return slot = INVALID_COMPANY;
}