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Fix excessive recursion in link graph refresher with conditional order loops

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This commit is contained in:
Jonathan G Rennison
2022-05-12 00:58:31 +01:00
parent c8043f6e00
commit dd40fa32df
2 changed files with 19 additions and 28 deletions
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40
src/linkgraph/refresh.cpp
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@@ -65,26 +65,6 @@
}
}
/**
* Comparison operator to allow hops to be used in a std::set.
* @param other Other hop to be compared with.
* @return If this hop is "smaller" than the other (defined by from, to and cargo in this order).
*/
bool LinkRefresher::Hop::operator<(const Hop &other) const
{
if (this->from < other.from) {
return true;
} else if (this->from > other.from) {
return false;
}
if (this->to < other.to) {
return true;
} else if (this->to > other.to) {
return false;
}
return this->cargo < other.cargo;
}
/**
* Constructor for link refreshing algorithm.
* @param vehicle Vehicle to refresh links for.
@@ -215,10 +195,17 @@ const Order *LinkRefresher::PredictNextOrder(const Order *cur, const Order *next
if (skip_to != nullptr && num_hops < std::min<uint>(64, this->vehicle->orders->GetNumOrders()) && skip_to != next) {
/* Make copies of capacity tracking lists. There is potential
* for optimization here: If the vehicle never refits we don't
* need to copy anything. Also, if we've seen the branched link
* before we don't need to branch at all. */
LinkRefresher branch(*this);
branch.RefreshLinks(cur, skip_to, flags, num_hops + 1);
* need to copy anything. */
/* Record the branch before executing it,
* to avoid recursively executing it again. */
Hop hop(cur->index, skip_to->index, this->cargo, flags);
auto iter = this->seen_hops->lower_bound(hop);
if (iter == this->seen_hops->end() || *iter != hop) {
this->seen_hops->insert(iter, hop);
LinkRefresher branch(*this);
branch.RefreshLinks(cur, skip_to, flags, num_hops + 1);
}
}
}
@@ -331,10 +318,11 @@ void LinkRefresher::RefreshLinks(const Order *cur, const Order *next, uint8 flag
next = this->PredictNextOrder(cur, next, flags, num_hops);
if (next == nullptr) break;
Hop hop(cur->index, next->index, this->cargo);
if (this->seen_hops->find(hop) != this->seen_hops->end()) {
auto iter = this->seen_hops->lower_bound(hop);
if (iter != this->seen_hops->end() && *iter == hop) {
break;
} else {
this->seen_hops->insert(hop);
this->seen_hops->insert(iter, hop);
}
/* Don't use the same order again, but choose a new one in the next round. */