src/helper/time_support.c

   1 /***************************************************************************
   2  *   Copyright (C) 2006 by Dominic Rath                                    *
   3  *   Dominic.Rath@gmx.de                                                   *
   4  *                                                                         *
   5  *   Copyright (C) 2007,2008 Øyvind Harboe                                 *
   6  *   oyvind.harboe@zylin.com                                               *
   7  *                                                                         *
   8  *   Copyright (C) 2008 by Spencer Oliver                                  *
   9  *   spen@spen-soft.co.uk                                                  *
  10  *                                                                         *
  11  *   This program is free software; you can redistribute it and/or modify  *
  12  *   it under the terms of the GNU General Public License as published by  *
  13  *   the Free Software Foundation; either version 2 of the License, or     *
  14  *   (at your option) any later version.                                   *
  15  *                                                                         *
  16  *   This program is distributed in the hope that it will be useful,       *
  17  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  18  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  19  *   GNU General Public License for more details.                          *
  20  *                                                                         *
  21  *   You should have received a copy of the GNU General Public License     *
  22  *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  23  ***************************************************************************/
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include "config.h"
  27 #endif
  28
  29 #include "time_support.h"
  30
  31 /* calculate difference between two struct timeval values */
  32 int timeval_subtract(struct timeval *result, struct timeval *x, struct timeval *y)
  33 {
  34         if (x->tv_usec < y->tv_usec) {
  35                 int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
  36                 y->tv_usec -= 1000000 * nsec;
  37                 y->tv_sec += nsec;
  38         }
  39         if (x->tv_usec - y->tv_usec > 1000000) {
  40                 int nsec = (x->tv_usec - y->tv_usec) / 1000000;
  41                 y->tv_usec += 1000000 * nsec;
  42                 y->tv_sec -= nsec;
  43         }
  44
  45         result->tv_sec = x->tv_sec - y->tv_sec;
  46         result->tv_usec = x->tv_usec - y->tv_usec;
  47
  48         /* Return 1 if result is negative. */
  49         return x->tv_sec < y->tv_sec;
  50 }
  51
  52 int timeval_add_time(struct timeval *result, long sec, long usec)
  53 {
  54         result->tv_sec += sec;
  55         result->tv_usec += usec;
  56
  57         while (result->tv_usec > 1000000) {
  58                 result->tv_usec -= 1000000;
  59                 result->tv_sec++;
  60         }
  61
  62         return 0;
  63 }
  64
  65 int duration_start(struct duration *duration)
  66 {
  67         return gettimeofday(&duration->start, NULL);
  68 }
  69
  70 int duration_measure(struct duration *duration)
  71 {
  72         struct timeval end;
  73         int retval = gettimeofday(&end, NULL);
  74         if (0 == retval)
  75                 timeval_subtract(&duration->elapsed, &end, &duration->start);
  76         return retval;
  77 }
  78
  79 float duration_elapsed(const struct duration *duration)
  80 {
  81         float t = duration->elapsed.tv_sec;
  82         t += (float)duration->elapsed.tv_usec / 1000000.0;
  83         return t;
  84 }
  85
  86 float duration_kbps(const struct duration *duration, size_t count)
  87 {
  88         return count / (1024.0 * duration_elapsed(duration));
  89 }