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//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2022
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#pragma once
#include "td/utils/common.h"
#include <limits>
namespace td {
// More strict implementaions of flood control than FloodControlFast.
// Should be just fine for small counters.
class FloodControlStrict {
public:
// there is no reason to return wakeup_at_, because it will be a time before the next allowed event, not current
void add_event(double now) {
events_.push_back(Event{now});
if (without_update_ > 0) {
without_update_--;
} else {
update(now);
}
}
// no more than count in each duration
void add_limit(int32 duration, size_t count) {
limits_.push_back(Limit{duration, count, 0});
without_update_ = 0;
}
double get_wakeup_at() const {
return wakeup_at_;
}
void clear_events() {
events_.clear();
for (auto &limit : limits_) {
limit.pos_ = 0;
}
without_update_ = 0;
wakeup_at_ = 0.0;
}
private:
void update(double now) {
size_t min_pos = events_.size();
without_update_ = std::numeric_limits<size_t>::max();
for (auto &limit : limits_) {
if (limit.count_ < events_.size() - limit.pos_) {
limit.pos_ = events_.size() - limit.count_;
}
// binary-search? :D
auto end_time = now - limit.duration_;
while (limit.pos_ < events_.size() && events_[limit.pos_].timestamp_ < end_time) {
limit.pos_++;
}
if (limit.count_ + limit.pos_ <= events_.size()) {
CHECK(limit.count_ + limit.pos_ == events_.size());
wakeup_at_ = max(wakeup_at_, events_[limit.pos_].timestamp_ + limit.duration_);
without_update_ = 0;
} else {
without_update_ = min(without_update_, limit.count_ + limit.pos_ - events_.size() - 1);
}
min_pos = min(min_pos, limit.pos_);
}
if (min_pos * 2 > events_.size()) {
for (auto &limit : limits_) {
limit.pos_ -= min_pos;
}
events_.erase(events_.begin(), events_.begin() + min_pos);
}
}
double wakeup_at_ = 0.0;
struct Event {
double timestamp_;
};
struct Limit {
int32 duration_;
size_t count_;
size_t pos_;
};
size_t without_update_ = 0;
vector<Event> events_;
vector<Limit> limits_;
};
} // namespace td
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