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// counter.h
/**
* Copyright (C) 2008-2012 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects
* for all of the code used other than as permitted herein. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you do not
* wish to do so, delete this exception statement from your version. If you
* delete this exception statement from all source files in the program,
* then also delete it in the license file.
*/
#pragma once
#include "mongo/platform/atomic_word.h"
#include "mongo/platform/cstdint.h"
namespace mongo {
/**
* A 64bit (atomic) counter.
*
* The constructor allows setting the start value, and increment([int]) is used to change it.
*
* The value can be returned using get() or the (long long) function operator.
*/
class Counter64 {
public:
/** Atomically increment. */
void increment( uint64_t n = 1 ) { _counter.addAndFetch(n); }
/** Atomically decrement. */
void decrement( uint64_t n = 1 ) { _counter.subtractAndFetch(n); }
/** Return the current value */
long long get() const { return _counter.load(); }
operator long long() const { return get(); }
private:
AtomicInt64 _counter;
};
}
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