util.c

// Part of readsb, a Mode-S/ADSB/TIS message decoder.
//
// util.c: misc utilities
//
// Copyright (c) 2019 Michael Wolf <michael@mictronics.de>
//
// This code is based on a detached fork of dump1090-fa.
//
// Copyright (c) 2015 Oliver Jowett <oliver@mutability.co.uk>
//
// This file is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// any later version.
//
// This file 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
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
//
// This file incorporates work covered by the following copyright and
// license:
//
// Copyright (C) 2012 by Salvatore Sanfilippo <antirez@gmail.com>
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//  *  Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
//
//  *  Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in the
//     documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "readsb.h"

#include <stdlib.h>
#include <sys/time.h>

uint64_t _messageNow = 0;

uint64_t mstime(void) {
    struct timeval tv;
    uint64_t mst;

    gettimeofday(&tv, NULL);
    mst = ((uint64_t) tv.tv_sec)*1000;
    mst += tv.tv_usec / 1000;
    return mst;
}

int64_t receiveclock_ns_elapsed(uint64_t t1, uint64_t t2) {
    return (t2 - t1) * 1000U / 12U;
}

int64_t receiveclock_ms_elapsed(uint64_t t1, uint64_t t2) {
    return (t2 - t1) / 12000U;
}

void normalize_timespec(struct timespec *ts) {
    if (ts->tv_nsec > 1000000000) {
        ts->tv_sec += ts->tv_nsec / 1000000000;
        ts->tv_nsec = ts->tv_nsec % 1000000000;
    } else if (ts->tv_nsec < 0) {
        long adjust = ts->tv_nsec / 1000000000 + 1;
        ts->tv_sec -= adjust;
        ts->tv_nsec = (ts->tv_nsec + 1000000000 * adjust) % 1000000000;
    }
}

/* record current CPU time in start_time */
void start_cpu_timing(struct timespec *start_time) {
    clock_gettime(CLOCK_THREAD_CPUTIME_ID, start_time);
}

/* add difference between start_time and the current CPU time to add_to, return elapsed time */
int64_t end_cpu_timing(const struct timespec *start_time, struct timespec *add_to) {
    struct timespec end_time;
    clock_gettime(CLOCK_THREAD_CPUTIME_ID, &end_time);
    add_to->tv_sec += end_time.tv_sec - start_time->tv_sec;
    add_to->tv_nsec += end_time.tv_nsec - start_time->tv_nsec;
    normalize_timespec(add_to);
    return ((int64_t) end_time.tv_sec * 1000UL + end_time.tv_nsec / 1000000UL)
        - ((int64_t) start_time->tv_sec * 1000UL + start_time->tv_nsec / 1000000UL);
}