85 lines
2.7 KiB
C++
85 lines
2.7 KiB
C++
#ifndef _2Q_CACHE_H_
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#define _2Q_CACHE_H_
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#include <iostream>
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#include <unordered_map>
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#include <list>
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class TwoCache {
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private:
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//2 LRU caches
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size_t cpct_q1;
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std::unordered_map<int, std::list<int>::iterator> umap1;
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std::list <int> q1; //fast queue - the most popular pages
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size_t cpct_q2;
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std::unordered_map<int, std::list<int>::iterator> umap2;
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std::list <int> q2; //slow queue - if page asked at the first time put it to q2, if itasked from q2 it put it to q1,
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public:
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TwoCache(size_t q1sz, size_t q2sz): cpct_q1(q1sz), cpct_q2(q2sz) {} //ctor
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void put_page(int id) {
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if (umap1.find(id) != umap1.end()) { //page is found, nothing to do (fast case)
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return;
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} else if (umap2.find(id) != umap2.end()) {
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q2.erase(umap2[id]); //if page is in slow put it in fast
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if (q1.size() < cpct_q1) {
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q1.push_front(id);
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umap1[id] = q1.begin();
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} else {
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int lru_page = q1.back(); //if fast is overflow - delete
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q1.pop_back();
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umap1.erase(lru_page);
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q1.push_front(id);
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umap1[id] = q1.begin();
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}
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return;
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} else if (q2.size() < cpct_q2) { //if not in cache put it in slow
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q2.push_front(id);
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umap2[id] = q2.begin();
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return;
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} else { //if slow is overflow - pop
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int lru_page = q2.back();
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q2.pop_back();
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umap2.erase(lru_page);
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q2.push_front(id);
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umap2[id] = q2.begin();
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return;
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}
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}
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void print_info() {
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std::cout << "\nq1 (the most usable): ";
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for (auto i = q1.begin(); i != q1.end(); i++) {
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std::cout << *i << " ";
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}
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std::cout << "\nq2 (Less usable): ";
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for (auto i = q2.begin(); i != q2.end(); i++) {
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std::cout << *i << " ";
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}
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std::cout << std::endl;
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}
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std::string string_info () { //to easy compare with tests;
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std::string answer;
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for (auto i = q1.begin(); i != q1.end(); i++) {
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answer += std::to_string(*i) + " ";
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}
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for (auto i = q2.begin(); i != q2.end(); i++) {
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answer += std::to_string(*i) + " ";
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}
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answer.pop_back(); //delete last space
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return answer;
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}
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};
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#endif |