src/common/time.c

   1 /*
   2  * Copyright (C) 2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License, version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 51
  15  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #include <common/time.h>
  19 #include <common/macros.h>
  20 #include <stddef.h>
  21 #include <stdint.h>
  22 #include <limits.h>
  23 #include <errno.h>
  24 #include <pthread.h>
  25
  26 LTTNG_HIDDEN
  27 int timespec_to_ms(struct timespec ts, unsigned long *ms)
  28 {
  29         unsigned long res, remain_ms;
  30
  31         if (ts.tv_sec > ULONG_MAX / MSEC_PER_SEC) {
  32                 errno = EOVERFLOW;
  33                 return -1;      /* multiplication overflow */
  34         }
  35         res = ts.tv_sec * MSEC_PER_SEC;
  36         remain_ms = ULONG_MAX - res;
  37         if (ts.tv_nsec / NSEC_PER_MSEC > remain_ms) {
  38                 errno = EOVERFLOW;
  39                 return -1;      /* addition overflow */
  40         }
  41         res += ts.tv_nsec / NSEC_PER_MSEC;
  42         *ms = res;
  43         return 0;
  44 }
  45
  46 LTTNG_HIDDEN
  47 struct timespec timespec_abs_diff(struct timespec t1, struct timespec t2)
  48 {
  49         uint64_t ts1 = (uint64_t) t1.tv_sec * (uint64_t) NSEC_PER_SEC +
  50                         (uint64_t) t1.tv_nsec;
  51         uint64_t ts2 = (uint64_t) t2.tv_sec * (uint64_t) NSEC_PER_SEC +
  52                         (uint64_t) t2.tv_nsec;
  53         uint64_t diff = max(ts1, ts2) - min(ts1, ts2);
  54         struct timespec res;
  55
  56         res.tv_sec = diff / (uint64_t) NSEC_PER_SEC;
  57         res.tv_nsec = diff % (uint64_t) NSEC_PER_SEC;
  58         return res;
  59 }