ibrdtn/ibrdtn/utils/Clock.cpp

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/*
 * Clock.cpp
 *
 *  Created on: 24.06.2010
 *      Author: morgenro
 */

#include "ibrdtn/utils/Clock.h"
#include <sys/time.h>

namespace dtn
{
        namespace utils
        {
                int Clock::timezone = 0;
                float Clock::quality = 0;

                u_int32_t Clock::TIMEVAL_CONVERSION = 946684800;

                Clock::Clock()
                {
                }

                Clock::~Clock()
                {
                }

                size_t Clock::getExpireTime(size_t timestamp, size_t lifetime)
                {
                        // if the quality of time is zero, return standard expire time
                        if (Clock::quality == 0) return timestamp + lifetime;

                        // calculate sigma based on the quality of time and the original lifetime
                        size_t sigma = lifetime * (1 - Clock::quality);

                        // expiration adjusted by quality of time
                        return timestamp + lifetime + sigma;
                }

                bool Clock::isExpired(size_t timestamp, size_t lifetime)
                {
                        // if the quality of time is zero, then never expire a bundle
                        if (Clock::quality == 0) return false;

                        if (lifetime > 0)
                        {
                                // calculate sigma based on the quality of time and the original lifetime
                                size_t sigma = lifetime * (1 - Clock::quality);

                                // expiration adjusted by quality of time
                                if ( Clock::getTime() > (timestamp + sigma)) return true;
                        }
                        else
                        {
                                // expiration based on the timestamp only
                                if ( Clock::getTime() > timestamp) return true;
                        }

                        return false;
                }

                size_t Clock::getTime()
                {
                        struct timeval now;
                        ::gettimeofday(&now, 0);

                        // timezone
                        int offset = Clock::timezone * 3600;

                        // do we believe we are before the year 2000?
                        if ((u_int)now.tv_sec < TIMEVAL_CONVERSION)
                        {
                                return 0;
                        }

                        return (now.tv_sec - TIMEVAL_CONVERSION) + offset;
                }
        }
}

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