81 lines
1.8 KiB
C++
81 lines
1.8 KiB
C++
#pragma once
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#include <iostream>
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#include <list>
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#include <stdexcept>
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#include <unordered_map>
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namespace NGame {
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template<typename Key, typename Value>
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class TLRU {
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public:
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using TPair = std::pair<Key, Value>;
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using TKey = Key;
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using TValue = Value;
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TLRU(std::size_t capacity)
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: Capacity_(capacity) {
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}
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const Value& Get(const Key& key) const {
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auto it = Map_.find(key);
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if (it == Map_.end()) {
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throw std::runtime_error("lru cache miss");
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}
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Cache_.splice(Cache_.begin(), Cache_, it->second);
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return it->second->second;
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}
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void Set(const Key& key, const Value& value) {
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Set(key, value, [](auto& value){});
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}
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template<typename UnaryPredicate>
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void Set(const Key& key, const Value& value, UnaryPredicate p) {
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auto it = Map_.find(key);
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if (it != Map_.end()) {
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p(*it->second);
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Cache_.erase(it->second);
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Map_.erase(it);
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}
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Cache_.push_front(std::make_pair(key, value));
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Map_[key] = Cache_.begin();
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while (Map_.size() > Capacity_) {
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auto lastElement = --(Cache_.end());
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p(*lastElement);
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Map_.erase(lastElement->first);
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Cache_.erase(lastElement);
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}
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}
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bool Contains(const Key& key) const {
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return Map_.find(key) != Map_.end();
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}
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std::size_t Size() const {
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return Map_.size();
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}
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std::size_t Capacity() const {
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return Capacity_;
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}
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void Clear() {
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Cache_.clear();
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Map_.clear();
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}
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private:
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using TIterator = typename std::list<TPair>::iterator;
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mutable std::list<TPair> Cache_;
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mutable std::unordered_map<Key, TIterator> Map_;
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std::size_t Capacity_;
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};
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} // namespace NGame
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