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/*
* Copyright 2021 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <cstddef>
#include <map>
#include <mutex>
#include <unordered_map>
#include <vector>
template <typename T>
class SyncMapCount {
public:
struct Item {
T item;
size_t count;
};
private:
std::map<const T, std::size_t> map_;
size_t max_size_{SIZE_MAX};
mutable std::mutex mutex_;
std::vector<Item> Vectorize() const {
std::vector<Item> vec;
for (auto& it : this->Get()) {
vec.push_back(Item{it.first, it.second});
}
return vec;
}
std::vector<Item> GetSorted(std::function<bool(const Item& a, const Item& b)> sort_func) const {
std::vector<Item> vec = Vectorize();
sort(vec.begin(), vec.end(), [=](const Item& a, const Item& b) -> bool { return sort_func(a, b); });
return vec;
}
public:
SyncMapCount() : max_size_(SIZE_MAX) {}
explicit SyncMapCount(size_t max_size) : max_size_(max_size) {}
~SyncMapCount() = default;
void Put(const T item) {
std::unique_lock<std::mutex> lock(mutex_);
if (map_.size() == max_size_) return;
(map_.count(item) > 0) ? map_[item] += 1 : map_[item] = 1;
}
std::map<const T, std::size_t> Get() const {
std::unique_lock<std::mutex> lock(mutex_);
return map_;
}
std::size_t Size() const {
std::unique_lock<std::mutex> lock(mutex_);
return map_.size();
}
void Clear() {
std::unique_lock<std::mutex> lock(mutex_);
map_.clear();
}
std::vector<Item> GetSortedHighToLow() const {
return GetSorted([](const Item& a, const Item& b) -> bool { return a.count > b.count; });
}
std::vector<Item> GetSortedLowToHigh() const {
return GetSorted([](const Item& a, const Item& b) -> bool { return a.count < b.count; });
}
};
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