mpls_util.c

/* Copyright (C) 2016 Cumulus Networks
 *                    Donald Sharp <sharpd@cumulusnetworks.com>
 *
 * This file is part of mpls_util.
 *
 * mpls_util 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 2 of the License, or
 * (at your option) any later version.
 *
 * mpls_util 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 mpls_util.  If not, see <http://www.gnu.org/licenses/>
 */
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <sys/time.h>
#include <sys/types.h>
#include "mpls_util.h"

void
mpls_util_ntp_to_unix_time (ntp_time_t *ntp, struct timeval *tv)
{
  tv->tv_sec = ntp->seconds - 0x83AA7E80;
  tv->tv_usec = (uint32_t)((double)ntp->fraction * 1.0e6 / (double)(1LL<<32));
}

void
mpls_util_unix_to_ntp_time (struct timeval *tv, ntp_time_t *ntp)
{
  ntp->seconds = tv->tv_sec + 0x83AA7E80;
  ntp->fraction = (uint32_t)( (double)(tv->tv_usec+1) * (double)(1LL<<32) * 1.0e-6 );
}


void
mpls_util_timeval_subtract (struct timeval *result, struct timeval *x, struct timeval *y)
{
  /* Perform the carry for the later subtraction by updating y. */
  if (x->tv_usec < y->tv_usec) {
    int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
    y->tv_usec -= 1000000 * nsec;
    y->tv_sec += nsec;
  }
  if (x->tv_usec - y->tv_usec > 1000000) {
    int nsec = (x->tv_usec - y->tv_usec) / 1000000;
    y->tv_usec += 1000000 * nsec;
    y->tv_sec -= nsec;
  }

  /* Compute the time remaining to wait.
     tv_usec is certainly positive. */
  result->tv_sec = x->tv_sec - y->tv_sec;
  result->tv_usec = x->tv_usec - y->tv_usec;

}