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tdlib-fork/tdutils/td/utils/ThreadSafeCounter.h

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//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2019
//
// 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/port/thread.h"
#include "td/utils/port/thread_local.h"
#include "td/utils/int_types.h"
#include <atomic>
#include <array>
namespace td {
class ThreadSafeCounter {
public:
void add(int64 diff) {
auto &node = thread_local_node();
node.count_.store(node.count_.load(std::memory_order_relaxed) + diff, std::memory_order_relaxed);
}
int64 sum() const {
int n = max_thread_id_.load();
int64 res = 0;
for (int i = 0; i < n; i++) {
res += nodes_[i].count_.load();
}
return res;
}
private:
struct Node {
std::atomic<int64> count_{0};
char padding[128];
};
static constexpr int MAX_THREAD_ID = 128;
std::atomic<int> max_thread_id_{MAX_THREAD_ID};
std::array<Node, MAX_THREAD_ID> nodes_;
Node &thread_local_node() {
auto thread_id = get_thread_id();
CHECK(0 <= thread_id && static_cast<size_t>(thread_id) < nodes_.size());
return nodes_[thread_id];
}
};
} // namespace td