TimeMeasurement.cpp

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/*
 * TimeMeasurement.cpp
 *
 * Copyright (C) 2011 IBR, TU Braunschweig
 *
 * Written-by: Johannes Morgenroth <morgenroth@ibr.cs.tu-bs.de>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include "ibrcommon/config.h"
#include "ibrcommon/TimeMeasurement.h"
#include <iostream>
#include <iomanip>
#include <stdio.h>

#ifdef HAVE_FEATURES_H
#include <features.h>
#endif

#ifdef HAVE_MACH_MACH_TIME_H
#include <mach/mach_time.h>
#include <mach/clock.h>
#include <mach/mach.h>
#endif

namespace ibrcommon
{
        TimeMeasurement::TimeMeasurement()
        {
                start(); stop();
        }

        TimeMeasurement::~TimeMeasurement()
        {
        }

        void TimeMeasurement::start()
        {
                // set start time
                gettime(&_start);
        }

        void TimeMeasurement::stop()
        {
                // set stop time
                gettime(&_end);
        }

        double TimeMeasurement::getMilliseconds() const
        {
                struct timespec diff;
                getTime(diff);

                // merge seconds and nanoseconds
                double delay_us = ((double)diff.tv_sec * 1000.0) + ((double)diff.tv_nsec / 1000000.0);

                return delay_us;
        }

        double TimeMeasurement::getMicroseconds() const
        {
                struct timespec diff;
                getTime(diff);

                // merge seconds and nanoseconds
                double delay_us = ((double)diff.tv_sec * 1000000.0) + ((double)diff.tv_nsec / 1000.0);

                return delay_us;
        }

        time_t TimeMeasurement::getSeconds() const
        {
                return _end.tv_sec - _start.tv_sec;
        }

        std::ostream& TimeMeasurement::format(std::ostream &stream, const double value)
        {
#ifdef __UCLIBC__
                char buf[32];
                snprintf(buf, 32, "%4.2f", value);
                stream << std::string(buf);
#else
                stream << std::setiosflags(std::ios::fixed) << std::setprecision(2) << value;
#endif
                return stream;
        }

        std::ostream &operator<<(std::ostream &stream, const TimeMeasurement &measurement)
        {
                struct timespec diff;
                measurement.getTime(diff);

                // convert nanoseconds to milliseconds
                double delay_ms = (double)diff.tv_nsec / 1000000.0;

                if (diff.tv_sec < 1)
                {
                        TimeMeasurement::format(stream, delay_ms); stream << " ms";
                        return stream;
                }

                // convert time interval to seconds
                double seconds = (double)diff.tv_sec + (delay_ms / 1000.0);

                if (diff.tv_sec >= 3600)
                {
                        TimeMeasurement::format(stream, seconds / 3600.0); stream << " h";
                }
                else if (diff.tv_sec >= 60)
                {
                        TimeMeasurement::format(stream, seconds / 60.0); stream << " m";
                }
                else
                {
                        TimeMeasurement::format(stream, seconds); stream << " s";
                }

                return stream;
        }

        void TimeMeasurement::getTime(struct timespec &diff) const
        {
                if ((_end.tv_nsec - _start.tv_nsec) < 0)
                {
                        diff.tv_sec = _end.tv_sec - _start.tv_sec - 1;
                        diff.tv_nsec = (1000000000 + _end.tv_nsec) - _start.tv_nsec;
                }
                else
                {
                        diff.tv_sec = _end.tv_sec - _start.tv_sec;
                        diff.tv_nsec = _end.tv_nsec - _start.tv_nsec;
                }
        }

        void TimeMeasurement::gettime(struct timespec *ts)
        {
#ifdef HAVE_MACH_MACH_TIME_H // OS X does not have clock_gettime, use clock_get_time
                clock_serv_t cclock;
                mach_timespec_t mts;
                host_get_clock_service(mach_host_self(), REALTIME_CLOCK, &cclock);
                clock_get_time(cclock, &mts);
                mach_port_deallocate(mach_task_self(), cclock);
                ts->tv_sec = mts.tv_sec;
                ts->tv_nsec = mts.tv_nsec;
#else
                ::clock_gettime(CLOCK_MONOTONIC, ts);
#endif
        }
}