87 lines
2.1 KiB
C++
87 lines
2.1 KiB
C++
//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2018
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#pragma once
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#include "td/utils/common.h"
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#include "td/utils/misc.h"
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#include <set>
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namespace td {
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template <class ValueT>
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class Enumerator {
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public:
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using Key = int32;
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template <class T>
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Key add(T &&value) {
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ValueT v = std::forward<T>(value);
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container_->set_zero_value(&v);
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auto it = set_.lower_bound(Key{0});
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container_->set_zero_value(nullptr);
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if (it != set_.end() && container_->get_value(*it) == v) {
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return *it;
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}
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auto key = container_->add_value(std::move(v));
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set_.insert(it, key);
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return key;
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}
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ValueT &get(Key key) {
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return container_->get_value(key);
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}
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const ValueT &get(Key key) const {
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return container_->get_value(key);
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}
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private:
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class Container {
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public:
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bool compare(Key a, Key b) const {
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return get_value(a) < get_value(b);
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}
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const ValueT &get_value(Key key) const {
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if (key == 0) {
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CHECK(zero_value_);
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return *zero_value_;
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}
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size_t pos = narrow_cast<size_t>(key - 1);
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CHECK(pos < values_.size());
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return values_[pos];
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}
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ValueT &get_value(Key key) {
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return const_cast<ValueT &>(const_cast<const Container *>(this)->get_value(key));
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}
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void set_zero_value(ValueT *value) {
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zero_value_ = value;
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}
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Key add_value(ValueT &&value) {
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values_.push_back(std::move(value));
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return narrow_cast<Key>(values_.size());
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}
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private:
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std::vector<ValueT> values_;
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ValueT *zero_value_ = nullptr;
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};
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class Comparator {
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public:
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explicit Comparator(Container *container) : container_(container) {
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}
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bool operator()(Key a, Key b) const {
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return container_->compare(a, b);
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}
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private:
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Container *container_;
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};
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std::unique_ptr<Container> container_{std::make_unique<Container>()};
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std::set<Key, Comparator> set_{Comparator{container_.get()}};
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};
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} // namespace td
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