// @file mongo/util/timer.cpp

/*    Copyright 2009 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
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 *    then also delete it in the license file.
 */

#include "mongo/platform/basic.h"

#include "mongo/util/timer.h"

#include "mongo/util/system_tick_source.h"
#include "mongo/util/tick_source.h"

namespace mongo {

namespace {

    const int64_t kMicrosPerSecond = 1000 * 1000;

} // unnamed namespace

    Timer::Timer(): Timer(SystemTickSource::get()) {
    }

    Timer::Timer(TickSource* tickSource):
            _tickSource(tickSource),
            _microsPerCount(static_cast<double>(kMicrosPerSecond) /
                            _tickSource->getTicksPerSecond()) {
        reset();
    }

    long long Timer::now() const {
        return _tickSource->getTicks();
    }

}  // namespace mongo