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, write to the                         *
  23  *   Free Software Foundation, Inc.,                                       *
  24  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  25  ***************************************************************************/
  26 #ifdef HAVE_CONFIG_H
  27 #include "config.h"
  28 #endif
  29
  30 #include "time_support.h"
  31
  32 /* calculate difference between two struct timeval values */
  33 int timeval_subtract(struct timeval *result, struct timeval *x, struct timeval *y)
  34 {
  35         if (x->tv_usec < y->tv_usec)
  36         {
  37                 int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
  38                 y->tv_usec -= 1000000 * nsec;
  39                 y->tv_sec += nsec;
  40         }
  41         if (x->tv_usec - y->tv_usec > 1000000) {
  42                 int nsec = (x->tv_usec - y->tv_usec) / 1000000;
  43                 y->tv_usec += 1000000 * nsec;
  44                 y->tv_sec -= nsec;
  45         }
  46
  47         result->tv_sec = x->tv_sec - y->tv_sec;
  48         result->tv_usec = x->tv_usec - y->tv_usec;
  49
  50         /* Return 1 if result is negative. */
  51         return x->tv_sec < y->tv_sec;
  52 }
  53
  54 /* add two struct timeval values */
  55 int timeval_add(struct timeval *result, struct timeval *x, struct timeval *y)
  56 {
  57         memcpy(result, x, sizeof(struct timeval));
  58         return timeval_add_time(result, y->tv_sec, y->tv_usec);
  59 }
  60
  61 int timeval_add_time(struct timeval *result, long sec, long usec)
  62 {
  63         result->tv_sec += sec;
  64         result->tv_usec += usec;
  65
  66         while (result->tv_usec > 1000000)
  67         {
  68                 result->tv_usec -= 1000000;
  69                 result->tv_sec++;
  70         }
  71
  72         return 0;
  73 }
  74
  75 int duration_start(struct duration *duration)
  76 {
  77         return gettimeofday(&duration->start, NULL);
  78 }
  79
  80 int duration_measure(struct duration *duration)
  81 {
  82         struct timeval end;
  83         int retval = gettimeofday(&end, NULL);
  84         if (0 == retval)
  85                 timeval_subtract(&duration->elapsed, &end, &duration->start);
  86         return retval;
  87 }
  88
  89 float duration_elapsed(struct duration *duration)
  90 {
  91         float t = duration->elapsed.tv_sec;
  92         t += (float)duration->elapsed.tv_usec / 1000000.0;
  93         return t;
  94 }
  95
  96 float duration_kbps(struct duration *duration, size_t count)
  97 {
  98         return count / (1024.0 * duration_elapsed(duration));
  99 }