65 lines
2.0 KiB
C++
65 lines
2.0 KiB
C++
// Copyright (c) 2012 The Bitcoin developers
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// Distributed under the MIT/X11 software license, see the accompanying
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// file license.txt or http://www.opensource.org/licenses/mit-license.php.
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#ifndef BITCOIN_MRUSET_H
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#define BITCOIN_MRUSET_H
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#include <set>
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#include <deque>
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/** STL-like set container that only keeps the most recent N elements. */
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template <typename T> class mruset
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{
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public:
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typedef T key_type;
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typedef T value_type;
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typedef typename std::set<T>::iterator iterator;
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typedef typename std::set<T>::const_iterator const_iterator;
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typedef typename std::set<T>::size_type size_type;
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protected:
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std::set<T> set;
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std::deque<T> queue;
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size_type nMaxSize;
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public:
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mruset(size_type nMaxSizeIn = 0) { nMaxSize = nMaxSizeIn; }
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iterator begin() const { return set.begin(); }
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iterator end() const { return set.end(); }
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size_type size() const { return set.size(); }
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bool empty() const { return set.empty(); }
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iterator find(const key_type& k) const { return set.find(k); }
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size_type count(const key_type& k) const { return set.count(k); }
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bool inline friend operator==(const mruset<T>& a, const mruset<T>& b) { return a.set == b.set; }
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bool inline friend operator==(const mruset<T>& a, const std::set<T>& b) { return a.set == b; }
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bool inline friend operator<(const mruset<T>& a, const mruset<T>& b) { return a.set < b.set; }
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std::pair<iterator, bool> insert(const key_type& x)
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{
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std::pair<iterator, bool> ret = set.insert(x);
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if (ret.second)
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{
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if (nMaxSize && queue.size() == nMaxSize)
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{
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set.erase(queue.front());
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queue.pop_front();
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}
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queue.push_back(x);
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}
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return ret;
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}
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size_type max_size() const { return nMaxSize; }
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size_type max_size(size_type s)
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{
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if (s)
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while (queue.size() >= s)
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{
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set.erase(queue.front());
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queue.pop_front();
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}
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nMaxSize = s;
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return nMaxSize;
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}
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};
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#endif
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