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f6f99919da
They will be re-used for collecting encoding statistics which is needed to write SSTables 3.0. Part of #1969. Signed-off-by: Vladimir Krivopalov <vladimir@scylladb.com>
66 lines
1.5 KiB
C++
66 lines
1.5 KiB
C++
/*
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* Copyright (C) 2018 ScyllaDB
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*/
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/*
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* This file is part of Scylla.
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*
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* Scylla is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Scylla is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <functional>
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namespace detail {
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template<typename T, typename Comparator>
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class extremum_tracker {
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T _default_value;
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bool _is_set = false;
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T _value;
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public:
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extremum_tracker() {}
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explicit extremum_tracker(T default_value) {
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_default_value = default_value;
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}
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void update(T value) {
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if (!_is_set) {
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_value = value;
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_is_set = true;
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} else {
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if (Comparator{}(value,_value)) {
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_value = value;
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}
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}
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}
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T get() const {
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if (_is_set) {
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return _value;
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}
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return _default_value;
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}
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};
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} // namespace detail
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template <typename T>
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using min_tracker = detail::extremum_tracker<T, std::less<T>>;
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template <typename T>
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using max_tracker = detail::extremum_tracker<T, std::greater<T>>;
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